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PlGF and Doppler ultrasound parameters in SGA pregnancies with confirmed neonatal birth weight below 10th percentile
Accepted Manuscript sFlt-1/PlGF and Doppler ultrasound parameters in SGA pregnancies with confirmed neonatal birth weight below 10th percentile Sebastian Kwiatkowski, Magdalena Bednarek-Jędrzejek, Joanna Ksel, Piotr Tousty, Ewa Kwiatkowska, Aneta Cymbaluk, Rafał Rzepka, Anita ChudeckaGłaz, Barbara Doł ęgowska, Andrzej Torbè PII: DOI: Reference:
S2210-7789(18)30136-3 https://doi.org/10.1016/j.preghy.2018.08.448 PREGHY 499
To appear in:
Pregnancy Hypertension: An International Journal of Women's Cardiovascular Health
Received Date: Revised Date: Accepted Date:
21 May 2018 2 August 2018 15 August 2018
Please cite this article as: Kwiatkowski, S., Bednarek-Jędrzejek, M., Ksel, J., Tousty, P., Kwiatkowska, E., Cymbaluk, A., Rzepka, R., Chudecka-Głaz, A., Doł ęgowska, B., Torbè, A., sFlt-1/PlGF and Doppler ultrasound parameters in SGA pregnancies with confirmed neonatal birth weight below 10th percentile, Pregnancy Hypertension: An International Journal of Women's Cardiovascular Health (2018), doi: https://doi.org/10.1016/ j.preghy.2018.08.448
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Low neonatal birth weight versus the sFlt-1/PlGF ratio and Doppler ultrasound parameters. sFlt-1/PlGF and Doppler ultrasound parameters in SGA pregnancies with confirmed neonatal birth weight below 10th percentile Sebastian Kwiatkowski1, Magdalena Bednarek-Jędrzejek1, Joanna Ksel1, Piotr Tousty1, Ewa Kwiatkowska2, Aneta Cymbaluk3, Rafał Rzepka1, Anita Chudecka-Głaz3, Barbara Dołęgowska4, Andrzej Torbè1 1. Department of Obstetrics and Gynecology, Pomeranian Medical University, Szczecin, Poland 2. Department of Nephrology, Transplantology and Internal Medicine, Pomeranian Medical University, Szczecin, Poland 3. Department of Gynecological Surgery and Gynecological Oncology of Adults and Adolescents, Pomeranian Medical University, Szczecin, Poland 4. Department of Microbiology, Immunology and Laboratory Medicine, Pomeranian Medical University, Szczecin, Poland
Corresponding author: Sebastian Kwiatkowski, [email protected], Department of Obstetrics and Gynecology, Pomeranian Medical University, Powstańców Wielkopolskich 72;70-111 Szczecin, Poland
Abstract: We explored whether there was a relationship between the sFlt-1/PlGF ratio in early-late and late-onset SGA patients and whether it is associated with can affect neonatal birth weight. Material/methods: 110 patients who were diagnosed with a fetal weight below the 10th percentile for gestational age and who at the same time delivered neonates with a birth weight below the 10th percentile for gestational age. For each of the patients sFlt-1, PlGF and the sFlt-1/PlGF ratio were studied and uterine artery (UtA) and umbilical artery (UA) Doppler were performed. Results: sFlt-1/PlGF ratios and neonatal birth weight which showed significant negative correlation across the entire population studied (R=- 0.46, p<0.001). In late-onset SGA patients this negative correlation was observed, as well (R = - 0.54, p<0.001) In the group of patients with pregnancies older than 34 weeks and an sFlt-1/PlGF ratio ≥38, we observed a significantly lower neonatal birth weight when compared to the same gestational age group with an sFlt-1/PlGF ratio <38 (2045 g vs 2405 g , p<0.001). Conclusion: Late-onset SGA syndromes are characterized by lower sFlt-1/PlGF ratios, which indicates a lower degree of placental function impairment. The sFlt-1/PlGF ratio can be a predictor of more significant growth disorders and a lower neonatal birth weight. The sFlt1/PlGF ratio can be helpful in distinguishing between disordered angiogenesis-dependent and other causes of late-onset SGA cases
Keywords: sFlt-1/PlGF ratio, UtA Doppler, low neonatal birth weight
Fetal growth restriction is an obstetric complication presenting a considerable challenge to perinatologists both during pregnancy while carrying out diagnostic tests and monitoring the fetus, and postpartum while treating the neonate. There are many causes of fetal growth disorders, from congenital defects to infections to genetic disorders to placental insufficiency [1]. Presently, attempts are being made to find better methods for diagnosing and monitoring fetuses that have developed growth disorders. Contemporary placental SGA assessment methods are based on ultrasound examinations, fetal weight estimations and Doppler ultrasound examinations, the latter of which is – according to the current standards – also useful in monitoring fetal status and can provide the grounds for a decision to terminate the pregnancy [2]. Many authors have noted that a distinction should be made between the early- and lateonset types of the disorder [3]. In the case of the placental origin of the pathology, earlyonset SGA – i.e. one occurring prior to 34 weeks of gestation – is caused by impaired trophoblast invasion, whereas late-onset SGA develops as a result of progressing placental insufficiency that develops too early[4]. Gratacos and Figueras propose that fetuses demonstrating placental dysfunction should be monitored using ultrasound parameters. The parameters developed by these authors are being used more and more commonly in many perinatal centers [5]. The question is, however, whether or not this has been the last word there is to say as it comes to diagnosing
fetal development under placental insufficiency conditions. The experience gained so far has shown that the highest sensitivity and specificity in prenatal diagnosis were obtained by combining biophysical and biochemical methods. Disordered angiogenesis is one of the processes that are inherently connected with the development of placental insufficiency [6]. Its diagnostic significance has increased even more the moment markers for assessing its severity were made commercially available. sFlt-1, PlGF and the sFlt-1/PlGF ratio determined on the basis of their values are becoming more and more acknowledged by those involved in diagnosing preeclampsia. We have attempted to assess the behavior of angiogenesis markers in both early- and late-onset SGA fetuses. The purpose of our retrospective research was to assess the disordered angiogenesis markers in fetuses with an estimated weight value below the 10th percentile for gestational age that at the same time had a birth weight below the 10th percentile, where the delivery resulted from induction or cesarean section for fetal reasons. We analyzed the ways in which angiogenesis markers correlated with Doppler ultrasound parameters and other parameters used in traditional diagnostic methods depending on the duration of gestation. We explored whether there was a relationship between the sFlt1/PlGF ratio in late-onset SGA patients and the diagnostic markers used so far and whether it can affect neonatal birth weight.
Material and methods The retrospective research was carried out on 128 patients, 18, all after 34th week of gestation were excluded after birth cause neonatal weight above 10 percentile. Analyzed material were 110 patients hospitalized in the Department of Obstetrics and Gynecology,
Pomeranian Medical University, Szczecin, Poland between 2015 and 2017, who were diagnosed with a fetal weight below the 10th percentile for gestational age and who at the same time delivered neonates with a birth weight below the 10th percentile for gestational age. Birth weight percentile were calculated according to Fenton Growth Charts (https://www.ucalgary.ca/fenton/). Cases of SGA caused by a genetic factor, infection (diagnostic amniocentesis was performed on some patients, while others were examined postpartum) or maternal factors were excluded from the SGA group. The study group was further divided into two groups. Group 1 (early-onset SGA fetuses) included patients whose pregnancies were terminated prior to 34 weeks of gestation (n=48). Group 2 (late-onset SGA fetuses) included patients who delivered after 34 weeks of gestation (n=62). The late-onset SGA patients were further divided into two subgroups. The first subgroup consisted of cases with an sFlt-1/PlGF ratio below 38, while the second one included patients with an sFlt1/PlGF ratio exceeding 38. In all of these cases, the delivery was performed because of fetal distress indicated by the clinical status of the fetus, i.e. abnormal CTG readings, improper flow patterns in Doppler ultrasound, a lack of fetal weight growth during the observation period, and an abnormal biophysical profile. In all of these patients, SGA was the primary clinical sign, while some of them developed the signs of gestational hypertension or preeclampsia in the course of their hospitalization. Apart from the SGA syndrome, 9 patients in the early-onset group also developed preeclampsia and 2 others demonstrated gestational hypertension. In the late-onset group, no preeclampsia was observed, with 8 patients developing gestational hypertension. For each of the fetuses, an ultrasound examination was performed for weight estimations, and uterine artery (UtA) and umbilical artery (UA) Doppler studies were performed, while for each of the vessels their pulsatility index (PI) and resistivity index (RI) were determined. For
the uterine arteries, the mean PI and RI values were determined on the basis of both left and right artery measurements. Gestational hypertension was defined as a blood pressure of 140/90 mm Hg detected at >20 weeks of gestation without proteinuria, and without the emergence of preeclampsia by 12 weeks postpartum. Preeclampsia was diagnosed in patients demonstrating high blood pressure and new-onset proteinuria (> 0.3 g/24h in 24h urine collection). In the absence of proteinuria, preeclampsia was diagnosed as hypertension in association with thrombocytopenia (a platelet count of less than 100,000/ul), impaired liver function (blood activity of liver aminotransferases elevated to twice the normal activity), new-onset renal insufficiency (elevated serum creatinine levels exceeding 1.1 mg/dl), pulmonary edema, or new-onset cerebral or visual disturbances. For each of the patients sFlt-1, PlGF and the sFlt-1/PlGF ratio were studied. sFLT and PlGF were determined using the electrochemiluminescence method (ECLIA). The determination was performed on the Cobas e6000 analyzer using the Elecsys® reagent kits in the said Laboratory Medicine Department. Moreover, each patient had a routine biochemistry panel done: complete blood count, aspartate transaminase, alanine transaminase, and uric acid and coagulation system tests. All the routine tests were performed in the Laboratory Medicine Department of the 2nd Autonomous Teaching Hospital of the Pomeranian Medical University, Szczecin, Poland. The Department participates in external quality assurance programs run by the Laboratory Diagnostics Quality Testing Center, Łódź, Randox Laboratories – the International External Quality Assessment Scheme RIQAS, Labquality – the External Quality Assessment Scheme, and Sysmex Europe GmbH – the International Quality Assessment program / External Quality Control program.
The blood for these determinations was sampled upon the patients’ informed consent, and within the subsequent 30 minutes centrifuged and placed at a temperature of -80°C awaiting determination. The blood for routine biochemistry tests was sampled into standard test tubes and immediately transported to the Central Hospital’s laboratory. The study was carried out with the consent of the Bioethics Committee at the Pomeranian Medical University (no. n.KB-0012/122/12). Statistical analysis The results were subjected to statistical analysis, for which purpose software (StatSoft, Poland) was used. As the Shapiro-Wilk test showed that the distributions of the examined parameters were significantly different from normal (p < 0.05), we used the non-parametric Wilcoxon test, Mann-Whitney U test and the Spearman’s rank correlation test for the statistical analysis. For comparisons of the values of particular markers between the study subgroups, the ANOVA test was used. In order to carry out a factorial assessment of the correlations between the studied parameters, the multiple linear regression model was used, built using the procedures of stepwise regression by forward and backward selection.
Conflict of interest Sebastian Kwiatkowski has received lecture fees from Roche Diagnostics. The other authors do not report any conflicts of interest. The authors alone are responsible for the content and writing of this article.
Results
We found no significant differences between the early- and late-onset SGA groups in respect of the biochemical parameters studied, except for the ALT levels. The neonatal birth weight differences found resulted from the different durations of pregnancy. The sFlt-1 (p<0.01) and PlGF (p<0.001) concentrations, as well as the sFlt-1/PlGF (p<0.001) ratio value, were significantly higher in the early-onset SGA group than in the late-onset one. The UA flow patterns in Doppler ultrasound were different between the early- and late-onset groups (p<0.01). No such difference was observed in respect of these parameters measured in the uterine arteries (Table 1). Moreover, the early-onset group had significantly higher rates of cesarean sections, proteinuria, hypertension and, thus, preeclampsia. Only 10% of the earlyonset SGA patients demonstrated an sFlt-1/PlGF ratio below 38. For comparison, the number of such cases among the late-onset SGA patients reached 44% (Table 2). Another of our objectives was to assess similar clinical, ultrasound and biochemical parameters for the late-onset SGA group depending on the sFlt-1/PlGF ratio. The value of 38 was assumed as the cut-off point, according to the practice established in the literature. In the group with milder angiogenesis marker disorders, we found that the pregnant patients were significantly younger (p<0.05), had a lower body weight (p<0.01) and their pregnancies lasted longer (p<0.01). Between the two late-onset subgroups, no differences were observed in respect of UA flow patterns in Doppler ultrasound, but at the same time considerably higher UtA PI and RI parameters were identified in the subgroup of patients demonstrating higher values of angiogenesis markers (sFlt-1 and PlGF) and their ratios. For the ≥38 subgroup, we also
showed there that the systolic pressure (p<0.01), diastolic pressure (p<0.01), uric acid concentration (p<0.01) and ALT level (<0.05) values were significantly higher (Table 3). In the sFlt-1/PlGF ratio <38 group, we observed a significantly lower number of cesarean sections (p<0.01) and a lower prevalence of hypertension (p<0.01). No case of preeclampsia was found in either of the subgroups (Table 4). We proved that there was a significant positive correlation between the UtA PI values and the sFlt-1/PlGF ratios across the entire population studied (R=0.51, p<0.001) (Fig 1). This correlation was so strong that it was also confirmed for the smaller population of women with late-onset SGA fetuses (R=0.52, p<0.001) (Fig 2). We ran a similar analysis of the relationship between the sFlt-1/PlGF ratios and neonatal birth weight which showed that there was a significant negative correlation across the entire population studied (R=- 0.46, p<0.001) (Fig 3). In the smaller population of late-onset SGA patients this negative correlation was observed, as well (R = - 0.54, p<0.001) (Fig 4). In the group of patients with pregnancies older than 34 weeks and an sFlt-1/PlGF ratio ≥38, we observed a significantly lower neonatal birth weight when compared to the same gestational age group with an sFlt-1/PlGF ratio <38 (2045 g vs 2405 g , p<0.001). This difference remained significant even when taking into account earlier termination in the group with higher angiogenesis marker disorders (factorial ANOVA, F=5.32, p<0.0001). As the dependent variable, we analyzed neonatal birth weight values. As the independent variables, we introduced the values of such parameters as UtA PI, the sFlT/PlGF ratio, and the week of gestation. The factorial analysis allowed us to find that 72% of the neonatal birth weight variability was explained by the model using UtA PI, the sFlT/PlGF ratio and the week of gestation as the independent variables (Table 5).
Discussion A low neonatal birth weight is a negative prognostic factor, as it increases the risk of certain neonatal period complications [7] on the one hand, and such chronic diseases as diabetes mellitus, hypertension and renal conditions in adult life, on the other [8, 9]. SGA (small for gestational age) fetuses are defined as having neonatal birth weight below the 10th percentile [10]. Placental insufficiency is one of the main causes of fetal growth disorders. Depending on when placental dysfunction develops, the growth restriction is either characterized as having an early or late onset. Early-onset SGA syndromes originate in the first half of gestation and are elated to a considerably impaired trophoblast invasion. The diagnostic procedures to be used for assessing these conditions are rather obvious. Unfortunately, the therapeutic opportunities available are greatly limited. Conceivably, early prevention is the only tool out there that can help us reduce the prevalence of these conditions. However, in late-onset growth disorders early prediction is practically impossible due to the fact that their development is related to placental dysfunction that starts in the 30th weeks of gestation, which dysfunction in this type of pathology is too severe too[11, 12]. Most often, late-onset growth disorders develop unnoticed and in some cases may even lead to intrauterine fetal deaths [13]. In recent years such syndromes have been the subject of growing interest and a focus of more and more insightful research as the range of diagnostic tools at our disposal is expanding. Ultrasound is of primary usefulness here, where apart from assessing fetal weight it is used to measure Doppler flows in the uterine, umbilical and middle cerebral arteries [5]. However, the results of Doppler studies may be somewhat delayed in relation to the onset of the insufficiency. Cases have been reported
where no UA lesions were spotted despite the diagnosis of SGA fetuses [14]. Some studies have shown quite severe ischemic placental lesions despite the diagnosis of normal UA flows [15]. There is still a need for new diagnostic methods that allow for distinguishing between growth disorders and small but normally growing fetuses. The placenta produces the placental growth factor (PlGF), which participates in angiogenesis and vasculogenesis. During pregnancy sFLT-1, a soluble receptor for angiogenic factors from the VEGF family, is produced, too. sFLT-1 neutralizes VEGF’s and PlGF’s advantageous proangiogenic activity. In normal pregnancies, proangiogenic factors prevail. Most research carried out so far has shown that SGA and preeclampsia share a profile of angiogenesis marker changes [6,16]. They were particularly marked in early-onset SGA forms, which was confirmed by our research [17]. The soluble tyrosine kinase receptor is produced in large concentrations by the hypoxic trophoblast, which confirms that there is hypoxic placenta present in both forms of the condition[18]. In turn, the significantly lower PlGF concentration in the early-onset form of the condition may be indicative of a considerably reduced placental reserve which is unable to increase PlGF production to compensate for the shortage and maintain homeostasis between proangiogenic and antiangiogenic factors. In his research, Korzeniowski et al. proved that the ratio of angiogenic and antiangiogenic factors in blood serum reflected maternal vascular underperfusion changes in the placenta regardless of the clinical diagnosis [19]. Our research showed higher sFlt-1/PlGF ratio values in early-onset SGA patients, but also an increased prevalence of preeclampsia and definitely rarer normal values of the ratio, which was in agreement with the research results reported so far.
Our analyses attempted to explore whether angiogenesis markers in late-onset fetal SGA cases correlated with the ultrasound parameters, although our main focus as on their correlation with neonatal birth weight. We found that there were significant but moderate correlations between disordered angiogenesis markers sFlt-1 and PlGF on the one hand and Doppler flow parameters on the other. UtA flows correlated with the sFlt-1/PlGF ratio across the entire population studied, and they did so significantly in the late-onset group. What is interesting, We did not find any differences in absolute values between these groups. This could be explained by a progressing and developing placental insufficiency and a lack of gradual reduction – typical of physiological pregnancies – of the UtA Doppler flow parameters. Other authors, too, have assessed the correlations between sFlt-1/PlGF ratio values and flow parameters too, and proved that there is a significant relationship between the uterine artery flow parameters, angiogenesis marker values, and histopathological test results reflecting MVU (maternal vascular underperfusion) [13,19]. The values of umbilical artery flow parameters also demonstrated statistically significant correlations with angiogenesis markers across the entire population studied, although they were not very intense and did not exist where the analysis only included the late-onset group. This could indicate a weaker relationship between the intensity of changes in the placenta representing insufficiency and disordered angiogenesis on the one hand, and umbilical artery flows on the other, contrary to the uterine artery flows. Our analyses of the Doppler flows allowed us to find that the UtA parameters correlated with neonatal birth weight across the entire population studied, and such correlations were also found in the late-onset group studied separately. This could confirms a correlation
between the UtA Doppler flow picture and placental function impairment, which affects fetal growth. In the group of patients with a more remarkable placental dysfunction (sFlt1/PlGF ≥38) we observed that the patients were older and characterized by larger weight, higher prevalence of co-existing hypertension and the need for an earlier termination of pregnancy. This confirmed a relationship between placental function and factors increasing the risk of developing preeclampsia. In their reports, Vrachnis [20] and Wei-Bin Wu [21] showed a correlation between PlGF and neonatal birth weight. As it has been reported (14,18,22), the sFlt-1/PlGF ratio reflects the severity of ischemic processes in the placenta. The suggested cut-off point for patients with preeclampsia between the correct values and those indicating placental dysfunction is 38 [23,24]. The significantly lower neonatal birth weight that we found in the group of patients with abnormal sFlt-1/PlGF ratios, with similar findings made by Trunfo [25], shows that this marker can be used independently of ultrasound to suggest a growth impairment, particularly where ultrasound parameters are normal. These differences were also maintained after the duration of pregnancy was taken into account and adjusted. Our research showed that the angiogenesis markers can have normal values in late-onset SGA cases, and that they do so much more often than in the early-onset forms of the condition. This could be indicative of growth disorders of a nature different to those related to disordered angiogenesis, for instance abnormal umbilical cord insertion or impaired umbilical flows. Another cause of normal values occurring in late-onset forms of the condition can be expected to be found in the insufficient sensitivity and specificity of the studied markers. Also, account should be taken of the limitations of the methods for diagnosing late-onset SGA cases currently in use, which leads to their overdiagnosis. All these issues should be further explored.
Conclusions 1. Early-onset SGA syndromes present a similar disordered angiogenesis profile to preeclampsia 2. Late-onset SGA syndromes are characterized by lower sFlt-1/PlGF ratios, which indicates a lower degree of placental function impairment 3. The sFlt-1/PlGF ratio can be a predictor of more significant growth disorders and a lower neonatal birth weight 4. The sFlt-1/PlGF ratio can be helpful in distinguishing between disordered angiogenesis-dependent and other causes of late-onset SGA cases 5. The mutual relationships and correlations between Doppler studies, disordered angiogenesis and various clinical parameters suggest that both biophysical and biochemical methods should be used in diagnosing late-onset fetal growth disorders.
References 1. Maulik D, Evans JD, Ragolia L; Fetal growth restriction, Patoghenic mechanisms ; clinic Obstet Gynecology 2006;49: 219-227 2. Mureșan D, Rotar IC, Stamatian F. The usefulness of fetal Doppler evaluation in early versus late onset intrauterine growth restriction. Review of the literature. Med Ultrason. 2016 Mar;18(1):103-9
3. Frigueras F, Gratacos E ; Update on the Diagnosis and Classification of Fetal Growth Restriction and Proposal of a Stage-Based Management Protocol ; Fetal Diagn Ther 2014;36:86–98 4. Redman SW, Sargent IL, Staff AC; IFPA Senior Award Lecture: Making sense of preeclampsia – two placental causes of preeclampsia; Placenta 35, Suplemment A; Throphoblast research, 28(2014) S20-S25 5. Frigueras F, Gratacos E, Stage based approach to the management of fetal growth restriction; Prenatal Diagnosis 2014, 34, 655–659 6. Kwiatkowski S, Dołęgowska B, Kwiatkowska E, Rzepka R, Torbè A, Bednarek-Jędrzejek M.A Common Profile of Disordered Angiogenic Factor Production and the Exacerbation of Inflammation in Early Preeclampsia, Late Preeclampsia, and Intrauterine Growth Restriction. PLoS One. 2016 Oct 19;11(10): 7. Miller SL, Huppi PS & Mallard C 2016 The consequences of fetal growth restriction on brain structure 541 and neurodevelopmental outcome. J Physiol 594 807-823.
8. Anderson NH, Sadler LC, Stewart AW, McCowan LM. Maternal and pathological pregnancy characteristics in customised birthweight centiles and identification of atrisk small-for gestational-age infants: a retrospective cohort study. BJOG. 2012 Jun;119(7):848-56.
9. Demicheva E, Crispi F; Long-term follow-up of intrauterine growth restriction: cardiovascular 493 disorders. Fetal Diagn Ther 2014; 36: 143-15 10. Soothill PW, Bobrow CS, Holmes R; Small for gestational age is not diagnosis; Ultrasound Obstet Gynecol 1999; 4: 225-8
11. Rolnik DL, Wright D, Poon LCY, Syngelaki A, O'Gorman N, de Paco Matallana C, Akolekar R, Cicero S, Janga D, Singh M, Molina FS, Persico N, Jani JC, Plasencia W, Papaioannou G, Tenenbaum-Gavish K, Nicolaides K; ASPRE trial: performance of screening for preterm pre-eclampsia.; Ultrasound Obstet Gynecol. 2017 Oct;50(4):492-495. 12. Kwiatkowski S, Dołęgowska B, Kwiatkowska E et all Do the physiological aging of the placenta and the changes in angiogenesis marker sFlt-1 and PlGF concentrations predispose patients to late-onset preeclampsia? J Matern Fetal Neonatal Med. 2017 Aug 29:1-10. 13. Mecacci F, Serena C, Avagliano L, Cozzolino M, Baroni E, Rambaldi M, Simeone S, Castiglione F, Taddei G, Bulfamante G; Stillbirths at Term: Case Control Study of Risk Factors, Growth Status and Placental Histology; PLoS ONE 11(12):e0166514.doi:10.1371/journal. pone.0166514 14. Illa M, Growth deficit in term small for gestational fetuses with normal umbilical artery Doppler is associated with adverse outcome; Journal Perinatal Medicine 37(1): 48-52 15. Triunfo S et al. angiogenic factors at late-onset small for gestational age and histological placental underperfussion / Placenta 35 (2014) 398e40 16. Herraiz I, Dröge L, Gómez-Montes E, Henrich W, Galindo A, Verlohren S; Characterization of the Soluble fms-Like Tyrosine Kinase-1toPlacental Growth Factor Ratio in Pregnancies Complicated by Fetal Growth Restriction; Obstet Gynecol 2014;124:265–73 17. Lehnen H, Mosblech N, Reineke T, Puchooa A, Menke-Möllers I, Zechner U, Gembruch U; Prenatal Clinical Assessment of sFlt-1 (Soluble fms-like Tyrosine Kinase-
1)/PlGF (Placental Growth Factor) Ratio as a Diagnostic Tool for Preeclampsia, Pregnancy-induced Hypertension, and Proteinuria. Geburtshilfe Frauenheilkd. 2013 May;73(5):440-445. 18. Shinohara S, Uchida Y, Kasai M, Sunami R; Association between the high soluble fmslike tyrosine kinase-1 to placental growth factor ratio and adverse outcomes in asymptomatic women with early-onset fetal growth restriction; Hypertens Pregnancy. 2017 Aug;36(3):269-275 19. Korzeniewski SJ, Romero R, Chaiworapongsa T, Chaemsaithong P, Kim CJ, Kim YM, Kim JS, Yoon BH, Hassan SS, Yeo L.Maternal plasma angiogenic index-1 (placental growth factor/soluble vascular endothelial growth factor receptor-1) is a biomarker for the burden of placental lesions consistent with uteroplacental underperfusion: a longitudinal case-cohort study.Am J Obstet Gynecol. 2016 May;214(5):629.e1629.e17 20. Vrachnis N, Kalampokas E, Sifakis S, Vitoratos N, Kalampokas T, Botsis D & Iliodromiti Z 2013 570 Placental growth factor (PlGF): a key to optimizing fetal growth. J Matern Fetal Neonatal Med 571 26 995-1002 21. Wei-Bin Wu, Yue-Ying Xu，Wei-Wei Cheng, Bo Yuan , Jiu-Ru Zhao ,Yan-Lin Wang , Hui-Juan Zhang; Decreased PGF May Contribute to Trophoblast Dysfunction in Fetal 1 Growth Restriction 22. Parra-Saavedra M, Crovetto F, Triunfo S, Savchev S, Peguero A, Nadal A, Gratacos E Figueras F; association of doppler parameters with placental signs of underperfusion in late-onset small-for-gestational-age pregnancie; ultrasound obstet gynecol 2014; 44: 330–337
23. Verlohren S, Herraiz I, Lapaire O, Schlembach D, Zeisler H, Calda P, Sabria J, MarkfeldErol F, Galindo A, Schoofs K, Denk B, Stepan H New gestational phase-specific cutoff values for the use of the soluble fms-like tyrosine kinase-1/placental growth factor ratio as a diagnostic test for preeclampsia. Hypertension. 2014 Feb; 63(2):346-52 24. Zeisler H, Llurba E, Chantraine F, Vatish M, Staff AC, Sennstr¨om M, Olovsson M, Brennecke SP, Stepan H, Allegranza D, Dilba P, Schoedl M, Hund M, Verlohren S. Predictive value of the sFlt-1:PlGF ratio in women with suspected preeclampsia. N Engl J Med 2016; 374: 13–22 25. Triunfo T, Parra-Saavedra M, Victor Rodriguez-Sureda E, Crovetto F, Dominguez C, Gratacós E, Figueras F, Angiogenic Factors and Doppler Evaluation in Normally Growing Fetuses at Routine Third-Trimester Scan: Prediction of Subsequent Low Birth Weight, Fetal Diagn Ther DOI: Fetal Diagn Ther. 2016;40(1):13-20
Table 1. A description and statistical analysis of the early- and late-onset SGA study groups (MannWhitney U-test). Group
Early-onset (n=48)
Late-onset (n=62)
Parameters
Me(min-max)
Me(min-max)
p-value
Age (years)
27 (19-37)
28 (18-41)
ns
Parity
1 (1-4)
1 (1-4)
ns
Gravidity
1 (1-4)
1 (1-4)
ns
Weight (kg)
71 (54-123)
74 (55-128)
ns
Height (cm)
164 (150-178)
165 (153-181)
ns
31 (20-33)
36 (34-40)
<0.01
UA PI
1.17 (0.68-1.87)
0.96 (0.52-3.68)
<0.01
UA RI
0.71 (0.49-0.86)
0.63 (0.40-1.17)
<0.01
UtA PI
1.26 (0.43-2.77)
1.03 (0.47-2.59)
ns
UtA RI
0.65 (0.33-0.90)
0.60 (0.34-0.90)
ns
biochemical parameters UA (umol/L)
5.70 (3.7-11.6)
5.40 (2.60-8.60)
ns
AST (U/L)
18.50 (11-40)
18 (9-63)
ns
ALT (U/L)
16 (7-60)
19 (8-63)
<0.05
LDH (U/L)
191 (137-242)
194 (126-298)
ns
200 (111-470)
205.50 (130-329)
ns
RBC (x10 /L)
4.18 (3.69-4.82)
4.14 (3.37-5.08)
ns
Hb (mmol/L)
7.85 (6.8-9.5)
7.8 (6.1-9.4)
ns
Ht (%)
0.36 (0.31-0.42)
0.36 (0.29-0.42)
ns
WBC (x10 /L)
9.9 (5.95-21.25)
10.42 (6.89-22.63)
ns
Fibrinogen (g/L)
4.4 (2.3-6.0)
4.10 (2.4-7.0)
ns
APTT (s)
28.6 (23.4-36.3
26.95 (23.00-31.60)
ns
PT(s)
10.30 (9.0-11.8)
10.30 (9.3-11.4)
ns
BP systolic (mmHg)
130 (100-189)
129.00 (95-167)
ns
1
Gestation (weeks ) ultrasound
9
PLT (x10 /L) 12
9
BP diastolic (mmHg)
80 (60-113)
80 (50-113)
ns
sFlt-1 (pg/mL)
7916.50 (393-35602)
5484 (1059-36338)
<0.01
PlGF (pg/mL)
50.43 (13.5-432.9)
83.87 (12.95-1006)
<0.001
sFlt-1/PlGF ratio
146.63 (0.91-1391.79)
63.82 (1.82-608.17)
<0.001
Neonatal birth weight (g)
1320 (620-1740)
2155 (1420-2770)
<0.001
P-value – statistically significant differences between the study groups; Early-onset – patients with early-onset small for gestational age fetuses, Late-onset – patients wits late-onset small for gestational age fetuses, 1 – gestation weeks at delivery; UA PI – umbilical artery pulsatility index; UA RI – umbilical artery resistance index; UtA PI – uterine artery average pulsatility index, UtA RI – uterine artery average resistance index; UA – uric acid, BP diastolic - respiratory rate diastolic blood pressure; BP systolic – respiratory rate systolic blood pressure; PT – prothrombin time; APTT – activated partial thromboplastin time; WBC – white blood cell count; Ht – hematocrit; Hb – hemoglobin; RBC – red blood cell count; PLT – platelet count; LDH – lactate dehydrogenase; ALT – alanine transaminase; AST – aspartate transaminase; UA – uric acid; ns – not significant;
Table 2. A description and statistical analysis of the early- and late-onset SGA study groups (Wilcoxon test)
Groups Parameters Nulliparas Delivery route Vaginal C-section Proteinuria (A) Hypertension (B) Preeclampsia (A+B) sFlt-1/PlGF ratio n<38
early-onset (n=48) n (%) 36 (75)
late-onset (n=62) n (%) p-value 46 (74) ns
0 (0) 48 (100) 9 (19) 11 (23) 9 (19)
20 (32) 42 (67) 0 (0) 8 (13) 0 (0)
<0.001 <0.001 <0.001 <0.05 <0.001
5 (10)
27 (44)
<0.001
Table 3. A description and statistical analysis of the sFlt-1/PlGF ratio-dependent late-onset SGA study groups (a cut-off point of 38) (Mann-Whitney U-test). Group
sFlt-1/PlGF ratio <38 (n=27)
sFlt-1/PlGF ≥38 (n=35)
Parameters
Me (min-max) 26 (18-39)
Me (min-max) 30 (19-41)
p-value <0.05
1 (1-4)
1 (1-4)
Ns
1 (1-4)
1 (1-4)
Ns
70 (55-87.9)
76 (60-128)
<0.01
168 (153-181)
164 (154-175)
Ns
37 (34-39)
35 (34-40)
<0.01
0.93 (0.54-3.68)
1.06 (0.52-2.04)
Ns
0.61 (0.42-1.17)
0.67 (0.40-0.88)
Ns
0.68 (0.47-1.94)
1.19 (0.55-2.57)
<0.001
0.47 (0.34- 0.91)
0.63 (0.38-0.87)
<0.001
biochemical parameters UA(umol/L)
4.8 (2.60-6.500
5.45 (3.9-8.6)
<0.01
AST (U/L)
15.5 (10-40)
22 (9-63)
<0.05
ALT (U/L)
14 (8.00-57.00
19 (11-63)
Ns
LDH (U/L)
186.5 (126-215)
197 (161-298)
Ns
PLT(x109/L)
206 (139-303)
205 (130-329)
Ns
RBC (x1012/L)
4.14 (3.37-4.75)
4.13 (3.65-5.08)
Ns
Hb (mmol/L)
7.8 (7.00-9.20)
7.85 (610-9.40)
Ns
Ht (%)
0.36 (0.32-0.41)
0.36 (0.29-0.42)
Ns
11.15 (7.69-20.77)
9.66 (6.89-22.63)
Ns
Age (years) Parity Gravidity Weight (kg) Height (cm) Gestation (weeks1) ultrasound UA PI UA RI UtA PI UtA RI
9
WBC (x10 /L)
Fibrinogen (g/L)
4.4 (3.1-5.0)
4.1 (2.4-7.0)
Ns
APTT (s)
26.7 (23.4-31.6)
27.2 (23.0-30.6)
Ns
PT(s)
10.6 (9.7-11.2)
10.2 (9.3-11.4)
Ns
BP systolic (mmHg)
120 (95-160)
137 (100-167)
<0.01
BP diastolic (mmHg)
74 (50-100)
85 (60-113)
<0.01
sFlt-1 (pg/mL)
3737 (1059-8173)
8301 (3444-36338)
<0.001
PlGF (pg/mL)
241.35 (116.10-1006)
62.19 (12.95-132.20)
<0.001
sFlt-1/PlGF ratio
13.58 (1.86-37.61)
145.59 (49.41-608.17)
<0.001
Neonatal birth weight (g)
2405 (1420-2770)
2045 (1360-2710)
<0.001
P-value – statistically significant differences between the study groups; Early-onset – patients with early-onset small for gestational age fetuses, Late-onset – patients wits late-onset small for gestational age fetuses, 1 – gestation weeks at delivery; UA PI – umbilical artery pulsatility index; UA RI – umbilical artery resistance index; UtA PI – uterine artery average pulsatility index, UtA RI – uterine artery average resistance index; UA – uric acid, BP diastolic – respiratory rate diastolic blood pressure; BP systolic – respiratory rate systolic blood pressure; PT – prothrombin time; APTT – activated partial thromboplastin time; WBC – white blood cell count; Ht – hematocrit; Hb – hemoglobin; RBC – red blood cell count; PLT – platelet count; LDH – lactate dehydrogenase; ALT – alanine transaminase; AST – aspartate transaminase; UA – uric acid; ns – not significant;
Table 4. A description and statistical analysis of the late-onset SGA study groups according to the sFlt1/PlGF ratio (cut-off 38) (Wilcoxon test)
Groups Parameters Nulliparas Delivery route Vaginal C-section Proteinuria (A) Hypertension (B) Preeclampsia (A+B)
ratio <38 ratio≥38 (n=27) (n=35) n (%) n (%) p-value 19 (70) 27 (77) ns 14 (52) 13 (48) 0 (0) 0 (0)
6 (17) 29 (83) 0 (0) 8 (23)
<0.01 <0.01 ns <0.01
0 (0)
0 (0)
ns
Table 5. An analysis of the effects of the studied parameters on neonatal birth weight – multiple linear regression models.
Dependent variable
Independent variables
Partial correlation coefficients
β p Neonatal UtA PI -0.33 -0.49 0.003 birth weight sFlT/PlGF ratio -0.46 -0.38 0.0001 UtA PI -0.20 -0.34 0.01 sFlT/PlGF ratio -0.28 -0.44 0.0005 tydzień 0.62 +0.74 0.000001 UtA PI -0.27 -0.41 0.001 week +0.70 +0.76 0.000001 standardized coefficient in the regression equation; R2 – coefficient of determination.
R2 0.42
p 0.000001
0.72
0.000001
0.67
0.000001
2,8 2,6 2,4 2,2 2,0
UtA PI
1,8 1,6 1,4 1,2 1,0 0,8 0,6 0,4 0,2 -200
0
200
400
600
800
1000
1200
1400
sFlt-1/PlGF ratio Fig 1. The correlation between the uterine artery average pulsatility index (UtA PI) and the fms-like tyrosine kinase receptor 1 (sFlt1)/ placental growth factor (PlGF) ratio. A positive correlation between the sFlt-1/PlGF ratio and UtA PI was observed in the study population (r = 0.51, p<0.001) using Spearman’s correlation analysis.
1600
2,8 2,6 2,4 2,2 2,0
UtA PI
1,8 1,6 1,4 1,2 1,0 0,8 0,6 0,4 0,2 -100
0
100
200
300
400
500
600
700
sFtl-1/PlGF ratio
Fig 2. The correlation between the uterine artery average pulsatility index (UtA PI) and the fms-like tyrosine kinase receptor 1 (sFlt1)/ placental growth factor (PlGF) ratio. A positive correlation between the sFlt-1/PlGF ratio and UtA PI was observed also separately in the late-onset SGA group (r = 0.52, p<0.001) using Spearman’s correlation analysis.
3000 2800 2600
Newborn weight
2400 2200 2000 1800 1600 1400 1200 1000 800 600 400 -200
0
200
400
600
800
1000
1200
1400
1600
sFlt-1/PlGF ratio Fig 3. The correlation between neonatal birth weight and the fms-like tyrosine kinase receptor 1 (sFlt1)/ placental growth factor (PlGF) ratio. A negative correlation between neonatal birth weight and the sFlt-1/PlGF ratio was observed in the study population (r = -0.46, p<0.001) using Spearman’s correlation analysis.
3000 2800
Newborn weight
2600 2400 2200 2000 1800 1600 1400 1200 -100
0
100
200
300
400
500
600
sFlt-1/PlGF ratio Fig 4. The correlation between neonatal birth weight and the fms-like tyrosine kinase receptor 1 (sFlt1)/ placental growth factor (PlGF) ratio. A negative correlation between neonatal birth weight and the sFlt-1/PlGF ratio was observed also separately in the late-onset SGA group (r = -0.54, p<0.001) using Spearman’s correlation analysis.
700
3000 2800
Newborn weight
2600 2400 2200 2000 1800 1600 1400 1200 1
2
subgroups with late-onset SGA (sFlt-1/PlGF ratio cut-off 38) Fig 5. Neonatal birth weight distribution in the late-onset SGA group according to the sFlt-1/PlGF ratio (a cut-off point of 38). 1 – the <38 subgroup; 2 – the ≥38 subgroup (p<0.001). The factorial ANNOVA ruled out the significance of the pregnancy termination term on fetal weight depending on the sFlt/PlGF ratio (F 0.45; p – ns)
Literary sources Maulik D, Evans JD, Ragolia L; Fetal growth restriction, Patoghenic mechanisms ; clinic Obstet Gynecology 2006;49: 219-227
The purpose of our research was to assess the disordered angiogenesis markers in fetuses with an estimated weight value below the 10th percentile for gestational age that at the same time had a birth weight below the 10th percentile. We explored whether there was a relationship between the sFlt-1/PlGF ratio in early-late and late-onset SGA patients and whether it can affect neonatal birth weight. Late-onset SGA syndromes are characterized by lower sFlt-1/PlGF ratios, which indicates a lower degree of placental function impairment. The sFlt-1/PlGF ratio can be a predictor of more significant growth disorders and a lower neonatal birth weight.
S2210-7789(18)30136-3 https://doi.org/10.1016/j.preghy.2018.08.448 PREGHY 499
To appear in:
Pregnancy Hypertension: An International Journal of Women's Cardiovascular Health
Received Date: Revised Date: Accepted Date:
21 May 2018 2 August 2018 15 August 2018
Please cite this article as: Kwiatkowski, S., Bednarek-Jędrzejek, M., Ksel, J., Tousty, P., Kwiatkowska, E., Cymbaluk, A., Rzepka, R., Chudecka-Głaz, A., Doł ęgowska, B., Torbè, A., sFlt-1/PlGF and Doppler ultrasound parameters in SGA pregnancies with confirmed neonatal birth weight below 10th percentile, Pregnancy Hypertension: An International Journal of Women's Cardiovascular Health (2018), doi: https://doi.org/10.1016/ j.preghy.2018.08.448
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Low neonatal birth weight versus the sFlt-1/PlGF ratio and Doppler ultrasound parameters. sFlt-1/PlGF and Doppler ultrasound parameters in SGA pregnancies with confirmed neonatal birth weight below 10th percentile Sebastian Kwiatkowski1, Magdalena Bednarek-Jędrzejek1, Joanna Ksel1, Piotr Tousty1, Ewa Kwiatkowska2, Aneta Cymbaluk3, Rafał Rzepka1, Anita Chudecka-Głaz3, Barbara Dołęgowska4, Andrzej Torbè1 1. Department of Obstetrics and Gynecology, Pomeranian Medical University, Szczecin, Poland 2. Department of Nephrology, Transplantology and Internal Medicine, Pomeranian Medical University, Szczecin, Poland 3. Department of Gynecological Surgery and Gynecological Oncology of Adults and Adolescents, Pomeranian Medical University, Szczecin, Poland 4. Department of Microbiology, Immunology and Laboratory Medicine, Pomeranian Medical University, Szczecin, Poland
Corresponding author: Sebastian Kwiatkowski, [email protected], Department of Obstetrics and Gynecology, Pomeranian Medical University, Powstańców Wielkopolskich 72;70-111 Szczecin, Poland
Abstract: We explored whether there was a relationship between the sFlt-1/PlGF ratio in early-late and late-onset SGA patients and whether it is associated with can affect neonatal birth weight. Material/methods: 110 patients who were diagnosed with a fetal weight below the 10th percentile for gestational age and who at the same time delivered neonates with a birth weight below the 10th percentile for gestational age. For each of the patients sFlt-1, PlGF and the sFlt-1/PlGF ratio were studied and uterine artery (UtA) and umbilical artery (UA) Doppler were performed. Results: sFlt-1/PlGF ratios and neonatal birth weight which showed significant negative correlation across the entire population studied (R=- 0.46, p<0.001). In late-onset SGA patients this negative correlation was observed, as well (R = - 0.54, p<0.001) In the group of patients with pregnancies older than 34 weeks and an sFlt-1/PlGF ratio ≥38, we observed a significantly lower neonatal birth weight when compared to the same gestational age group with an sFlt-1/PlGF ratio <38 (2045 g vs 2405 g , p<0.001). Conclusion: Late-onset SGA syndromes are characterized by lower sFlt-1/PlGF ratios, which indicates a lower degree of placental function impairment. The sFlt-1/PlGF ratio can be a predictor of more significant growth disorders and a lower neonatal birth weight. The sFlt1/PlGF ratio can be helpful in distinguishing between disordered angiogenesis-dependent and other causes of late-onset SGA cases
Keywords: sFlt-1/PlGF ratio, UtA Doppler, low neonatal birth weight
Fetal growth restriction is an obstetric complication presenting a considerable challenge to perinatologists both during pregnancy while carrying out diagnostic tests and monitoring the fetus, and postpartum while treating the neonate. There are many causes of fetal growth disorders, from congenital defects to infections to genetic disorders to placental insufficiency [1]. Presently, attempts are being made to find better methods for diagnosing and monitoring fetuses that have developed growth disorders. Contemporary placental SGA assessment methods are based on ultrasound examinations, fetal weight estimations and Doppler ultrasound examinations, the latter of which is – according to the current standards – also useful in monitoring fetal status and can provide the grounds for a decision to terminate the pregnancy [2]. Many authors have noted that a distinction should be made between the early- and lateonset types of the disorder [3]. In the case of the placental origin of the pathology, earlyonset SGA – i.e. one occurring prior to 34 weeks of gestation – is caused by impaired trophoblast invasion, whereas late-onset SGA develops as a result of progressing placental insufficiency that develops too early[4]. Gratacos and Figueras propose that fetuses demonstrating placental dysfunction should be monitored using ultrasound parameters. The parameters developed by these authors are being used more and more commonly in many perinatal centers [5]. The question is, however, whether or not this has been the last word there is to say as it comes to diagnosing
fetal development under placental insufficiency conditions. The experience gained so far has shown that the highest sensitivity and specificity in prenatal diagnosis were obtained by combining biophysical and biochemical methods. Disordered angiogenesis is one of the processes that are inherently connected with the development of placental insufficiency [6]. Its diagnostic significance has increased even more the moment markers for assessing its severity were made commercially available. sFlt-1, PlGF and the sFlt-1/PlGF ratio determined on the basis of their values are becoming more and more acknowledged by those involved in diagnosing preeclampsia. We have attempted to assess the behavior of angiogenesis markers in both early- and late-onset SGA fetuses. The purpose of our retrospective research was to assess the disordered angiogenesis markers in fetuses with an estimated weight value below the 10th percentile for gestational age that at the same time had a birth weight below the 10th percentile, where the delivery resulted from induction or cesarean section for fetal reasons. We analyzed the ways in which angiogenesis markers correlated with Doppler ultrasound parameters and other parameters used in traditional diagnostic methods depending on the duration of gestation. We explored whether there was a relationship between the sFlt1/PlGF ratio in late-onset SGA patients and the diagnostic markers used so far and whether it can affect neonatal birth weight.
Material and methods The retrospective research was carried out on 128 patients, 18, all after 34th week of gestation were excluded after birth cause neonatal weight above 10 percentile. Analyzed material were 110 patients hospitalized in the Department of Obstetrics and Gynecology,
Pomeranian Medical University, Szczecin, Poland between 2015 and 2017, who were diagnosed with a fetal weight below the 10th percentile for gestational age and who at the same time delivered neonates with a birth weight below the 10th percentile for gestational age. Birth weight percentile were calculated according to Fenton Growth Charts (https://www.ucalgary.ca/fenton/). Cases of SGA caused by a genetic factor, infection (diagnostic amniocentesis was performed on some patients, while others were examined postpartum) or maternal factors were excluded from the SGA group. The study group was further divided into two groups. Group 1 (early-onset SGA fetuses) included patients whose pregnancies were terminated prior to 34 weeks of gestation (n=48). Group 2 (late-onset SGA fetuses) included patients who delivered after 34 weeks of gestation (n=62). The late-onset SGA patients were further divided into two subgroups. The first subgroup consisted of cases with an sFlt-1/PlGF ratio below 38, while the second one included patients with an sFlt1/PlGF ratio exceeding 38. In all of these cases, the delivery was performed because of fetal distress indicated by the clinical status of the fetus, i.e. abnormal CTG readings, improper flow patterns in Doppler ultrasound, a lack of fetal weight growth during the observation period, and an abnormal biophysical profile. In all of these patients, SGA was the primary clinical sign, while some of them developed the signs of gestational hypertension or preeclampsia in the course of their hospitalization. Apart from the SGA syndrome, 9 patients in the early-onset group also developed preeclampsia and 2 others demonstrated gestational hypertension. In the late-onset group, no preeclampsia was observed, with 8 patients developing gestational hypertension. For each of the fetuses, an ultrasound examination was performed for weight estimations, and uterine artery (UtA) and umbilical artery (UA) Doppler studies were performed, while for each of the vessels their pulsatility index (PI) and resistivity index (RI) were determined. For
the uterine arteries, the mean PI and RI values were determined on the basis of both left and right artery measurements. Gestational hypertension was defined as a blood pressure of 140/90 mm Hg detected at >20 weeks of gestation without proteinuria, and without the emergence of preeclampsia by 12 weeks postpartum. Preeclampsia was diagnosed in patients demonstrating high blood pressure and new-onset proteinuria (> 0.3 g/24h in 24h urine collection). In the absence of proteinuria, preeclampsia was diagnosed as hypertension in association with thrombocytopenia (a platelet count of less than 100,000/ul), impaired liver function (blood activity of liver aminotransferases elevated to twice the normal activity), new-onset renal insufficiency (elevated serum creatinine levels exceeding 1.1 mg/dl), pulmonary edema, or new-onset cerebral or visual disturbances. For each of the patients sFlt-1, PlGF and the sFlt-1/PlGF ratio were studied. sFLT and PlGF were determined using the electrochemiluminescence method (ECLIA). The determination was performed on the Cobas e6000 analyzer using the Elecsys® reagent kits in the said Laboratory Medicine Department. Moreover, each patient had a routine biochemistry panel done: complete blood count, aspartate transaminase, alanine transaminase, and uric acid and coagulation system tests. All the routine tests were performed in the Laboratory Medicine Department of the 2nd Autonomous Teaching Hospital of the Pomeranian Medical University, Szczecin, Poland. The Department participates in external quality assurance programs run by the Laboratory Diagnostics Quality Testing Center, Łódź, Randox Laboratories – the International External Quality Assessment Scheme RIQAS, Labquality – the External Quality Assessment Scheme, and Sysmex Europe GmbH – the International Quality Assessment program / External Quality Control program.
The blood for these determinations was sampled upon the patients’ informed consent, and within the subsequent 30 minutes centrifuged and placed at a temperature of -80°C awaiting determination. The blood for routine biochemistry tests was sampled into standard test tubes and immediately transported to the Central Hospital’s laboratory. The study was carried out with the consent of the Bioethics Committee at the Pomeranian Medical University (no. n.KB-0012/122/12). Statistical analysis The results were subjected to statistical analysis, for which purpose software (StatSoft, Poland) was used. As the Shapiro-Wilk test showed that the distributions of the examined parameters were significantly different from normal (p < 0.05), we used the non-parametric Wilcoxon test, Mann-Whitney U test and the Spearman’s rank correlation test for the statistical analysis. For comparisons of the values of particular markers between the study subgroups, the ANOVA test was used. In order to carry out a factorial assessment of the correlations between the studied parameters, the multiple linear regression model was used, built using the procedures of stepwise regression by forward and backward selection.
Conflict of interest Sebastian Kwiatkowski has received lecture fees from Roche Diagnostics. The other authors do not report any conflicts of interest. The authors alone are responsible for the content and writing of this article.
Results
We found no significant differences between the early- and late-onset SGA groups in respect of the biochemical parameters studied, except for the ALT levels. The neonatal birth weight differences found resulted from the different durations of pregnancy. The sFlt-1 (p<0.01) and PlGF (p<0.001) concentrations, as well as the sFlt-1/PlGF (p<0.001) ratio value, were significantly higher in the early-onset SGA group than in the late-onset one. The UA flow patterns in Doppler ultrasound were different between the early- and late-onset groups (p<0.01). No such difference was observed in respect of these parameters measured in the uterine arteries (Table 1). Moreover, the early-onset group had significantly higher rates of cesarean sections, proteinuria, hypertension and, thus, preeclampsia. Only 10% of the earlyonset SGA patients demonstrated an sFlt-1/PlGF ratio below 38. For comparison, the number of such cases among the late-onset SGA patients reached 44% (Table 2). Another of our objectives was to assess similar clinical, ultrasound and biochemical parameters for the late-onset SGA group depending on the sFlt-1/PlGF ratio. The value of 38 was assumed as the cut-off point, according to the practice established in the literature. In the group with milder angiogenesis marker disorders, we found that the pregnant patients were significantly younger (p<0.05), had a lower body weight (p<0.01) and their pregnancies lasted longer (p<0.01). Between the two late-onset subgroups, no differences were observed in respect of UA flow patterns in Doppler ultrasound, but at the same time considerably higher UtA PI and RI parameters were identified in the subgroup of patients demonstrating higher values of angiogenesis markers (sFlt-1 and PlGF) and their ratios. For the ≥38 subgroup, we also
showed there that the systolic pressure (p<0.01), diastolic pressure (p<0.01), uric acid concentration (p<0.01) and ALT level (<0.05) values were significantly higher (Table 3). In the sFlt-1/PlGF ratio <38 group, we observed a significantly lower number of cesarean sections (p<0.01) and a lower prevalence of hypertension (p<0.01). No case of preeclampsia was found in either of the subgroups (Table 4). We proved that there was a significant positive correlation between the UtA PI values and the sFlt-1/PlGF ratios across the entire population studied (R=0.51, p<0.001) (Fig 1). This correlation was so strong that it was also confirmed for the smaller population of women with late-onset SGA fetuses (R=0.52, p<0.001) (Fig 2). We ran a similar analysis of the relationship between the sFlt-1/PlGF ratios and neonatal birth weight which showed that there was a significant negative correlation across the entire population studied (R=- 0.46, p<0.001) (Fig 3). In the smaller population of late-onset SGA patients this negative correlation was observed, as well (R = - 0.54, p<0.001) (Fig 4). In the group of patients with pregnancies older than 34 weeks and an sFlt-1/PlGF ratio ≥38, we observed a significantly lower neonatal birth weight when compared to the same gestational age group with an sFlt-1/PlGF ratio <38 (2045 g vs 2405 g , p<0.001). This difference remained significant even when taking into account earlier termination in the group with higher angiogenesis marker disorders (factorial ANOVA, F=5.32, p<0.0001). As the dependent variable, we analyzed neonatal birth weight values. As the independent variables, we introduced the values of such parameters as UtA PI, the sFlT/PlGF ratio, and the week of gestation. The factorial analysis allowed us to find that 72% of the neonatal birth weight variability was explained by the model using UtA PI, the sFlT/PlGF ratio and the week of gestation as the independent variables (Table 5).
Discussion A low neonatal birth weight is a negative prognostic factor, as it increases the risk of certain neonatal period complications [7] on the one hand, and such chronic diseases as diabetes mellitus, hypertension and renal conditions in adult life, on the other [8, 9]. SGA (small for gestational age) fetuses are defined as having neonatal birth weight below the 10th percentile [10]. Placental insufficiency is one of the main causes of fetal growth disorders. Depending on when placental dysfunction develops, the growth restriction is either characterized as having an early or late onset. Early-onset SGA syndromes originate in the first half of gestation and are elated to a considerably impaired trophoblast invasion. The diagnostic procedures to be used for assessing these conditions are rather obvious. Unfortunately, the therapeutic opportunities available are greatly limited. Conceivably, early prevention is the only tool out there that can help us reduce the prevalence of these conditions. However, in late-onset growth disorders early prediction is practically impossible due to the fact that their development is related to placental dysfunction that starts in the 30th weeks of gestation, which dysfunction in this type of pathology is too severe too[11, 12]. Most often, late-onset growth disorders develop unnoticed and in some cases may even lead to intrauterine fetal deaths [13]. In recent years such syndromes have been the subject of growing interest and a focus of more and more insightful research as the range of diagnostic tools at our disposal is expanding. Ultrasound is of primary usefulness here, where apart from assessing fetal weight it is used to measure Doppler flows in the uterine, umbilical and middle cerebral arteries [5]. However, the results of Doppler studies may be somewhat delayed in relation to the onset of the insufficiency. Cases have been reported
where no UA lesions were spotted despite the diagnosis of SGA fetuses [14]. Some studies have shown quite severe ischemic placental lesions despite the diagnosis of normal UA flows [15]. There is still a need for new diagnostic methods that allow for distinguishing between growth disorders and small but normally growing fetuses. The placenta produces the placental growth factor (PlGF), which participates in angiogenesis and vasculogenesis. During pregnancy sFLT-1, a soluble receptor for angiogenic factors from the VEGF family, is produced, too. sFLT-1 neutralizes VEGF’s and PlGF’s advantageous proangiogenic activity. In normal pregnancies, proangiogenic factors prevail. Most research carried out so far has shown that SGA and preeclampsia share a profile of angiogenesis marker changes [6,16]. They were particularly marked in early-onset SGA forms, which was confirmed by our research [17]. The soluble tyrosine kinase receptor is produced in large concentrations by the hypoxic trophoblast, which confirms that there is hypoxic placenta present in both forms of the condition[18]. In turn, the significantly lower PlGF concentration in the early-onset form of the condition may be indicative of a considerably reduced placental reserve which is unable to increase PlGF production to compensate for the shortage and maintain homeostasis between proangiogenic and antiangiogenic factors. In his research, Korzeniowski et al. proved that the ratio of angiogenic and antiangiogenic factors in blood serum reflected maternal vascular underperfusion changes in the placenta regardless of the clinical diagnosis [19]. Our research showed higher sFlt-1/PlGF ratio values in early-onset SGA patients, but also an increased prevalence of preeclampsia and definitely rarer normal values of the ratio, which was in agreement with the research results reported so far.
Our analyses attempted to explore whether angiogenesis markers in late-onset fetal SGA cases correlated with the ultrasound parameters, although our main focus as on their correlation with neonatal birth weight. We found that there were significant but moderate correlations between disordered angiogenesis markers sFlt-1 and PlGF on the one hand and Doppler flow parameters on the other. UtA flows correlated with the sFlt-1/PlGF ratio across the entire population studied, and they did so significantly in the late-onset group. What is interesting, We did not find any differences in absolute values between these groups. This could be explained by a progressing and developing placental insufficiency and a lack of gradual reduction – typical of physiological pregnancies – of the UtA Doppler flow parameters. Other authors, too, have assessed the correlations between sFlt-1/PlGF ratio values and flow parameters too, and proved that there is a significant relationship between the uterine artery flow parameters, angiogenesis marker values, and histopathological test results reflecting MVU (maternal vascular underperfusion) [13,19]. The values of umbilical artery flow parameters also demonstrated statistically significant correlations with angiogenesis markers across the entire population studied, although they were not very intense and did not exist where the analysis only included the late-onset group. This could indicate a weaker relationship between the intensity of changes in the placenta representing insufficiency and disordered angiogenesis on the one hand, and umbilical artery flows on the other, contrary to the uterine artery flows. Our analyses of the Doppler flows allowed us to find that the UtA parameters correlated with neonatal birth weight across the entire population studied, and such correlations were also found in the late-onset group studied separately. This could confirms a correlation
between the UtA Doppler flow picture and placental function impairment, which affects fetal growth. In the group of patients with a more remarkable placental dysfunction (sFlt1/PlGF ≥38) we observed that the patients were older and characterized by larger weight, higher prevalence of co-existing hypertension and the need for an earlier termination of pregnancy. This confirmed a relationship between placental function and factors increasing the risk of developing preeclampsia. In their reports, Vrachnis [20] and Wei-Bin Wu [21] showed a correlation between PlGF and neonatal birth weight. As it has been reported (14,18,22), the sFlt-1/PlGF ratio reflects the severity of ischemic processes in the placenta. The suggested cut-off point for patients with preeclampsia between the correct values and those indicating placental dysfunction is 38 [23,24]. The significantly lower neonatal birth weight that we found in the group of patients with abnormal sFlt-1/PlGF ratios, with similar findings made by Trunfo [25], shows that this marker can be used independently of ultrasound to suggest a growth impairment, particularly where ultrasound parameters are normal. These differences were also maintained after the duration of pregnancy was taken into account and adjusted. Our research showed that the angiogenesis markers can have normal values in late-onset SGA cases, and that they do so much more often than in the early-onset forms of the condition. This could be indicative of growth disorders of a nature different to those related to disordered angiogenesis, for instance abnormal umbilical cord insertion or impaired umbilical flows. Another cause of normal values occurring in late-onset forms of the condition can be expected to be found in the insufficient sensitivity and specificity of the studied markers. Also, account should be taken of the limitations of the methods for diagnosing late-onset SGA cases currently in use, which leads to their overdiagnosis. All these issues should be further explored.
Conclusions 1. Early-onset SGA syndromes present a similar disordered angiogenesis profile to preeclampsia 2. Late-onset SGA syndromes are characterized by lower sFlt-1/PlGF ratios, which indicates a lower degree of placental function impairment 3. The sFlt-1/PlGF ratio can be a predictor of more significant growth disorders and a lower neonatal birth weight 4. The sFlt-1/PlGF ratio can be helpful in distinguishing between disordered angiogenesis-dependent and other causes of late-onset SGA cases 5. The mutual relationships and correlations between Doppler studies, disordered angiogenesis and various clinical parameters suggest that both biophysical and biochemical methods should be used in diagnosing late-onset fetal growth disorders.
References 1. Maulik D, Evans JD, Ragolia L; Fetal growth restriction, Patoghenic mechanisms ; clinic Obstet Gynecology 2006;49: 219-227 2. Mureșan D, Rotar IC, Stamatian F. The usefulness of fetal Doppler evaluation in early versus late onset intrauterine growth restriction. Review of the literature. Med Ultrason. 2016 Mar;18(1):103-9
3. Frigueras F, Gratacos E ; Update on the Diagnosis and Classification of Fetal Growth Restriction and Proposal of a Stage-Based Management Protocol ; Fetal Diagn Ther 2014;36:86–98 4. Redman SW, Sargent IL, Staff AC; IFPA Senior Award Lecture: Making sense of preeclampsia – two placental causes of preeclampsia; Placenta 35, Suplemment A; Throphoblast research, 28(2014) S20-S25 5. Frigueras F, Gratacos E, Stage based approach to the management of fetal growth restriction; Prenatal Diagnosis 2014, 34, 655–659 6. Kwiatkowski S, Dołęgowska B, Kwiatkowska E, Rzepka R, Torbè A, Bednarek-Jędrzejek M.A Common Profile of Disordered Angiogenic Factor Production and the Exacerbation of Inflammation in Early Preeclampsia, Late Preeclampsia, and Intrauterine Growth Restriction. PLoS One. 2016 Oct 19;11(10): 7. Miller SL, Huppi PS & Mallard C 2016 The consequences of fetal growth restriction on brain structure 541 and neurodevelopmental outcome. J Physiol 594 807-823.
8. Anderson NH, Sadler LC, Stewart AW, McCowan LM. Maternal and pathological pregnancy characteristics in customised birthweight centiles and identification of atrisk small-for gestational-age infants: a retrospective cohort study. BJOG. 2012 Jun;119(7):848-56.
9. Demicheva E, Crispi F; Long-term follow-up of intrauterine growth restriction: cardiovascular 493 disorders. Fetal Diagn Ther 2014; 36: 143-15 10. Soothill PW, Bobrow CS, Holmes R; Small for gestational age is not diagnosis; Ultrasound Obstet Gynecol 1999; 4: 225-8
11. Rolnik DL, Wright D, Poon LCY, Syngelaki A, O'Gorman N, de Paco Matallana C, Akolekar R, Cicero S, Janga D, Singh M, Molina FS, Persico N, Jani JC, Plasencia W, Papaioannou G, Tenenbaum-Gavish K, Nicolaides K; ASPRE trial: performance of screening for preterm pre-eclampsia.; Ultrasound Obstet Gynecol. 2017 Oct;50(4):492-495. 12. Kwiatkowski S, Dołęgowska B, Kwiatkowska E et all Do the physiological aging of the placenta and the changes in angiogenesis marker sFlt-1 and PlGF concentrations predispose patients to late-onset preeclampsia? J Matern Fetal Neonatal Med. 2017 Aug 29:1-10. 13. Mecacci F, Serena C, Avagliano L, Cozzolino M, Baroni E, Rambaldi M, Simeone S, Castiglione F, Taddei G, Bulfamante G; Stillbirths at Term: Case Control Study of Risk Factors, Growth Status and Placental Histology; PLoS ONE 11(12):e0166514.doi:10.1371/journal. pone.0166514 14. Illa M, Growth deficit in term small for gestational fetuses with normal umbilical artery Doppler is associated with adverse outcome; Journal Perinatal Medicine 37(1): 48-52 15. Triunfo S et al. angiogenic factors at late-onset small for gestational age and histological placental underperfussion / Placenta 35 (2014) 398e40 16. Herraiz I, Dröge L, Gómez-Montes E, Henrich W, Galindo A, Verlohren S; Characterization of the Soluble fms-Like Tyrosine Kinase-1toPlacental Growth Factor Ratio in Pregnancies Complicated by Fetal Growth Restriction; Obstet Gynecol 2014;124:265–73 17. Lehnen H, Mosblech N, Reineke T, Puchooa A, Menke-Möllers I, Zechner U, Gembruch U; Prenatal Clinical Assessment of sFlt-1 (Soluble fms-like Tyrosine Kinase-
1)/PlGF (Placental Growth Factor) Ratio as a Diagnostic Tool for Preeclampsia, Pregnancy-induced Hypertension, and Proteinuria. Geburtshilfe Frauenheilkd. 2013 May;73(5):440-445. 18. Shinohara S, Uchida Y, Kasai M, Sunami R; Association between the high soluble fmslike tyrosine kinase-1 to placental growth factor ratio and adverse outcomes in asymptomatic women with early-onset fetal growth restriction; Hypertens Pregnancy. 2017 Aug;36(3):269-275 19. Korzeniewski SJ, Romero R, Chaiworapongsa T, Chaemsaithong P, Kim CJ, Kim YM, Kim JS, Yoon BH, Hassan SS, Yeo L.Maternal plasma angiogenic index-1 (placental growth factor/soluble vascular endothelial growth factor receptor-1) is a biomarker for the burden of placental lesions consistent with uteroplacental underperfusion: a longitudinal case-cohort study.Am J Obstet Gynecol. 2016 May;214(5):629.e1629.e17 20. Vrachnis N, Kalampokas E, Sifakis S, Vitoratos N, Kalampokas T, Botsis D & Iliodromiti Z 2013 570 Placental growth factor (PlGF): a key to optimizing fetal growth. J Matern Fetal Neonatal Med 571 26 995-1002 21. Wei-Bin Wu, Yue-Ying Xu，Wei-Wei Cheng, Bo Yuan , Jiu-Ru Zhao ,Yan-Lin Wang , Hui-Juan Zhang; Decreased PGF May Contribute to Trophoblast Dysfunction in Fetal 1 Growth Restriction 22. Parra-Saavedra M, Crovetto F, Triunfo S, Savchev S, Peguero A, Nadal A, Gratacos E Figueras F; association of doppler parameters with placental signs of underperfusion in late-onset small-for-gestational-age pregnancie; ultrasound obstet gynecol 2014; 44: 330–337
23. Verlohren S, Herraiz I, Lapaire O, Schlembach D, Zeisler H, Calda P, Sabria J, MarkfeldErol F, Galindo A, Schoofs K, Denk B, Stepan H New gestational phase-specific cutoff values for the use of the soluble fms-like tyrosine kinase-1/placental growth factor ratio as a diagnostic test for preeclampsia. Hypertension. 2014 Feb; 63(2):346-52 24. Zeisler H, Llurba E, Chantraine F, Vatish M, Staff AC, Sennstr¨om M, Olovsson M, Brennecke SP, Stepan H, Allegranza D, Dilba P, Schoedl M, Hund M, Verlohren S. Predictive value of the sFlt-1:PlGF ratio in women with suspected preeclampsia. N Engl J Med 2016; 374: 13–22 25. Triunfo T, Parra-Saavedra M, Victor Rodriguez-Sureda E, Crovetto F, Dominguez C, Gratacós E, Figueras F, Angiogenic Factors and Doppler Evaluation in Normally Growing Fetuses at Routine Third-Trimester Scan: Prediction of Subsequent Low Birth Weight, Fetal Diagn Ther DOI: Fetal Diagn Ther. 2016;40(1):13-20
Table 1. A description and statistical analysis of the early- and late-onset SGA study groups (MannWhitney U-test). Group
Early-onset (n=48)
Late-onset (n=62)
Parameters
Me(min-max)
Me(min-max)
p-value
Age (years)
27 (19-37)
28 (18-41)
ns
Parity
1 (1-4)
1 (1-4)
ns
Gravidity
1 (1-4)
1 (1-4)
ns
Weight (kg)
71 (54-123)
74 (55-128)
ns
Height (cm)
164 (150-178)
165 (153-181)
ns
31 (20-33)
36 (34-40)
<0.01
UA PI
1.17 (0.68-1.87)
0.96 (0.52-3.68)
<0.01
UA RI
0.71 (0.49-0.86)
0.63 (0.40-1.17)
<0.01
UtA PI
1.26 (0.43-2.77)
1.03 (0.47-2.59)
ns
UtA RI
0.65 (0.33-0.90)
0.60 (0.34-0.90)
ns
biochemical parameters UA (umol/L)
5.70 (3.7-11.6)
5.40 (2.60-8.60)
ns
AST (U/L)
18.50 (11-40)
18 (9-63)
ns
ALT (U/L)
16 (7-60)
19 (8-63)
<0.05
LDH (U/L)
191 (137-242)
194 (126-298)
ns
200 (111-470)
205.50 (130-329)
ns
RBC (x10 /L)
4.18 (3.69-4.82)
4.14 (3.37-5.08)
ns
Hb (mmol/L)
7.85 (6.8-9.5)
7.8 (6.1-9.4)
ns
Ht (%)
0.36 (0.31-0.42)
0.36 (0.29-0.42)
ns
WBC (x10 /L)
9.9 (5.95-21.25)
10.42 (6.89-22.63)
ns
Fibrinogen (g/L)
4.4 (2.3-6.0)
4.10 (2.4-7.0)
ns
APTT (s)
28.6 (23.4-36.3
26.95 (23.00-31.60)
ns
PT(s)
10.30 (9.0-11.8)
10.30 (9.3-11.4)
ns
BP systolic (mmHg)
130 (100-189)
129.00 (95-167)
ns
1
Gestation (weeks ) ultrasound
9
PLT (x10 /L) 12
9
BP diastolic (mmHg)
80 (60-113)
80 (50-113)
ns
sFlt-1 (pg/mL)
7916.50 (393-35602)
5484 (1059-36338)
<0.01
PlGF (pg/mL)
50.43 (13.5-432.9)
83.87 (12.95-1006)
<0.001
sFlt-1/PlGF ratio
146.63 (0.91-1391.79)
63.82 (1.82-608.17)
<0.001
Neonatal birth weight (g)
1320 (620-1740)
2155 (1420-2770)
<0.001
P-value – statistically significant differences between the study groups; Early-onset – patients with early-onset small for gestational age fetuses, Late-onset – patients wits late-onset small for gestational age fetuses, 1 – gestation weeks at delivery; UA PI – umbilical artery pulsatility index; UA RI – umbilical artery resistance index; UtA PI – uterine artery average pulsatility index, UtA RI – uterine artery average resistance index; UA – uric acid, BP diastolic - respiratory rate diastolic blood pressure; BP systolic – respiratory rate systolic blood pressure; PT – prothrombin time; APTT – activated partial thromboplastin time; WBC – white blood cell count; Ht – hematocrit; Hb – hemoglobin; RBC – red blood cell count; PLT – platelet count; LDH – lactate dehydrogenase; ALT – alanine transaminase; AST – aspartate transaminase; UA – uric acid; ns – not significant;
Table 2. A description and statistical analysis of the early- and late-onset SGA study groups (Wilcoxon test)
Groups Parameters Nulliparas Delivery route Vaginal C-section Proteinuria (A) Hypertension (B) Preeclampsia (A+B) sFlt-1/PlGF ratio n<38
early-onset (n=48) n (%) 36 (75)
late-onset (n=62) n (%) p-value 46 (74) ns
0 (0) 48 (100) 9 (19) 11 (23) 9 (19)
20 (32) 42 (67) 0 (0) 8 (13) 0 (0)
<0.001 <0.001 <0.001 <0.05 <0.001
5 (10)
27 (44)
<0.001
Table 3. A description and statistical analysis of the sFlt-1/PlGF ratio-dependent late-onset SGA study groups (a cut-off point of 38) (Mann-Whitney U-test). Group
sFlt-1/PlGF ratio <38 (n=27)
sFlt-1/PlGF ≥38 (n=35)
Parameters
Me (min-max) 26 (18-39)
Me (min-max) 30 (19-41)
p-value <0.05
1 (1-4)
1 (1-4)
Ns
1 (1-4)
1 (1-4)
Ns
70 (55-87.9)
76 (60-128)
<0.01
168 (153-181)
164 (154-175)
Ns
37 (34-39)
35 (34-40)
<0.01
0.93 (0.54-3.68)
1.06 (0.52-2.04)
Ns
0.61 (0.42-1.17)
0.67 (0.40-0.88)
Ns
0.68 (0.47-1.94)
1.19 (0.55-2.57)
<0.001
0.47 (0.34- 0.91)
0.63 (0.38-0.87)
<0.001
biochemical parameters UA(umol/L)
4.8 (2.60-6.500
5.45 (3.9-8.6)
<0.01
AST (U/L)
15.5 (10-40)
22 (9-63)
<0.05
ALT (U/L)
14 (8.00-57.00
19 (11-63)
Ns
LDH (U/L)
186.5 (126-215)
197 (161-298)
Ns
PLT(x109/L)
206 (139-303)
205 (130-329)
Ns
RBC (x1012/L)
4.14 (3.37-4.75)
4.13 (3.65-5.08)
Ns
Hb (mmol/L)
7.8 (7.00-9.20)
7.85 (610-9.40)
Ns
Ht (%)
0.36 (0.32-0.41)
0.36 (0.29-0.42)
Ns
11.15 (7.69-20.77)
9.66 (6.89-22.63)
Ns
Age (years) Parity Gravidity Weight (kg) Height (cm) Gestation (weeks1) ultrasound UA PI UA RI UtA PI UtA RI
9
WBC (x10 /L)
Fibrinogen (g/L)
4.4 (3.1-5.0)
4.1 (2.4-7.0)
Ns
APTT (s)
26.7 (23.4-31.6)
27.2 (23.0-30.6)
Ns
PT(s)
10.6 (9.7-11.2)
10.2 (9.3-11.4)
Ns
BP systolic (mmHg)
120 (95-160)
137 (100-167)
<0.01
BP diastolic (mmHg)
74 (50-100)
85 (60-113)
<0.01
sFlt-1 (pg/mL)
3737 (1059-8173)
8301 (3444-36338)
<0.001
PlGF (pg/mL)
241.35 (116.10-1006)
62.19 (12.95-132.20)
<0.001
sFlt-1/PlGF ratio
13.58 (1.86-37.61)
145.59 (49.41-608.17)
<0.001
Neonatal birth weight (g)
2405 (1420-2770)
2045 (1360-2710)
<0.001
P-value – statistically significant differences between the study groups; Early-onset – patients with early-onset small for gestational age fetuses, Late-onset – patients wits late-onset small for gestational age fetuses, 1 – gestation weeks at delivery; UA PI – umbilical artery pulsatility index; UA RI – umbilical artery resistance index; UtA PI – uterine artery average pulsatility index, UtA RI – uterine artery average resistance index; UA – uric acid, BP diastolic – respiratory rate diastolic blood pressure; BP systolic – respiratory rate systolic blood pressure; PT – prothrombin time; APTT – activated partial thromboplastin time; WBC – white blood cell count; Ht – hematocrit; Hb – hemoglobin; RBC – red blood cell count; PLT – platelet count; LDH – lactate dehydrogenase; ALT – alanine transaminase; AST – aspartate transaminase; UA – uric acid; ns – not significant;
Table 4. A description and statistical analysis of the late-onset SGA study groups according to the sFlt1/PlGF ratio (cut-off 38) (Wilcoxon test)
Groups Parameters Nulliparas Delivery route Vaginal C-section Proteinuria (A) Hypertension (B) Preeclampsia (A+B)
ratio <38 ratio≥38 (n=27) (n=35) n (%) n (%) p-value 19 (70) 27 (77) ns 14 (52) 13 (48) 0 (0) 0 (0)
6 (17) 29 (83) 0 (0) 8 (23)
<0.01 <0.01 ns <0.01
0 (0)
0 (0)
ns
Table 5. An analysis of the effects of the studied parameters on neonatal birth weight – multiple linear regression models.
Dependent variable
Independent variables
Partial correlation coefficients
β p Neonatal UtA PI -0.33 -0.49 0.003 birth weight sFlT/PlGF ratio -0.46 -0.38 0.0001 UtA PI -0.20 -0.34 0.01 sFlT/PlGF ratio -0.28 -0.44 0.0005 tydzień 0.62 +0.74 0.000001 UtA PI -0.27 -0.41 0.001 week +0.70 +0.76 0.000001 standardized coefficient in the regression equation; R2 – coefficient of determination.
R2 0.42
p 0.000001
0.72
0.000001
0.67
0.000001
2,8 2,6 2,4 2,2 2,0
UtA PI
1,8 1,6 1,4 1,2 1,0 0,8 0,6 0,4 0,2 -200
0
200
400
600
800
1000
1200
1400
sFlt-1/PlGF ratio Fig 1. The correlation between the uterine artery average pulsatility index (UtA PI) and the fms-like tyrosine kinase receptor 1 (sFlt1)/ placental growth factor (PlGF) ratio. A positive correlation between the sFlt-1/PlGF ratio and UtA PI was observed in the study population (r = 0.51, p<0.001) using Spearman’s correlation analysis.
1600
2,8 2,6 2,4 2,2 2,0
UtA PI
1,8 1,6 1,4 1,2 1,0 0,8 0,6 0,4 0,2 -100
0
100
200
300
400
500
600
700
sFtl-1/PlGF ratio
Fig 2. The correlation between the uterine artery average pulsatility index (UtA PI) and the fms-like tyrosine kinase receptor 1 (sFlt1)/ placental growth factor (PlGF) ratio. A positive correlation between the sFlt-1/PlGF ratio and UtA PI was observed also separately in the late-onset SGA group (r = 0.52, p<0.001) using Spearman’s correlation analysis.
3000 2800 2600
Newborn weight
2400 2200 2000 1800 1600 1400 1200 1000 800 600 400 -200
0
200
400
600
800
1000
1200
1400
1600
sFlt-1/PlGF ratio Fig 3. The correlation between neonatal birth weight and the fms-like tyrosine kinase receptor 1 (sFlt1)/ placental growth factor (PlGF) ratio. A negative correlation between neonatal birth weight and the sFlt-1/PlGF ratio was observed in the study population (r = -0.46, p<0.001) using Spearman’s correlation analysis.
3000 2800
Newborn weight
2600 2400 2200 2000 1800 1600 1400 1200 -100
0
100
200
300
400
500
600
sFlt-1/PlGF ratio Fig 4. The correlation between neonatal birth weight and the fms-like tyrosine kinase receptor 1 (sFlt1)/ placental growth factor (PlGF) ratio. A negative correlation between neonatal birth weight and the sFlt-1/PlGF ratio was observed also separately in the late-onset SGA group (r = -0.54, p<0.001) using Spearman’s correlation analysis.
700
3000 2800
Newborn weight
2600 2400 2200 2000 1800 1600 1400 1200 1
2
subgroups with late-onset SGA (sFlt-1/PlGF ratio cut-off 38) Fig 5. Neonatal birth weight distribution in the late-onset SGA group according to the sFlt-1/PlGF ratio (a cut-off point of 38). 1 – the <38 subgroup; 2 – the ≥38 subgroup (p<0.001). The factorial ANNOVA ruled out the significance of the pregnancy termination term on fetal weight depending on the sFlt/PlGF ratio (F 0.45; p – ns)
Literary sources Maulik D, Evans JD, Ragolia L; Fetal growth restriction, Patoghenic mechanisms ; clinic Obstet Gynecology 2006;49: 219-227
The purpose of our research was to assess the disordered angiogenesis markers in fetuses with an estimated weight value below the 10th percentile for gestational age that at the same time had a birth weight below the 10th percentile. We explored whether there was a relationship between the sFlt-1/PlGF ratio in early-late and late-onset SGA patients and whether it can affect neonatal birth weight. Late-onset SGA syndromes are characterized by lower sFlt-1/PlGF ratios, which indicates a lower degree of placental function impairment. The sFlt-1/PlGF ratio can be a predictor of more significant growth disorders and a lower neonatal birth weight.