- Email: [email protected]
Could adverse perinatal outcome be predicted from intrapartum umbilical vessels Doppler in women with abnormal cardiotocography?
Middle East Fertility Society Journal (2013) 18, 268–272
Middle East Fertility Society
Middle East Fertility Society Journal www.mefsjournal.org www.sciencedirect.com
ORIGINAL ARTICLE
Could adverse perinatal outcome be predicted from intrapartum umbilical vessels Doppler in women with abnormal cardiotocography? Ebtesam Moustafa Kamal
*
Obstetrics & Gynecology Departments, Faculty of Medicine, Zagazig University Egypt Received 4 September 2012; accepted 12 November 2012 Available online 30 January 2013
KEYWORDS Intra partum Doppler; Cardiotocography; Umbilical vessels; Fetal distress
Abstract Objectives: To evaluate the value of umbilical artery and umbilical vein Doppler study in predicting adverse perinatal events in low risk women with abnormal cardiotocography during labor. Design: Prospective cohort study. Setting: Emergency unit of obstetrics & gynecology department, Royal Commission hospital, El Gubail Industrial City, Saudi Arabia. Population: Sixty-six women with uncomplicated pregnancy were classified according to cardiotocography (CTG) findings during the active phase of labor into, 33 cases with normal CTG (group 1) and 33 cases with pathological CTG (group 2). Colour Doppler study of the umbilical artery (UA) and umbilical vein (UV) were performed for both groups and the results were correlated to perinatal outcome. Main outcome measures: Meconium stained amniotic fluid, emergency Cesarean deliveries for suspected fetal distress. Apgar score at 1 and 5 min, UA and UV cord blood pH, and the need for neonatal intensive care unit (NICU) admission. Results: In the pathological CTG group two (6.1%) cases had high UA Doppler indices with no adverse perinatal outcome, while 13 (39.4%) cases showed UV pulsations of them 12 (92.3%) cases underwent emergency cesarean section for fetal distress, 5 (38.4%) cases delivered babies with UV pH < 7.2. Normal UA Doppler indices and no UV pulsations were seen in all cases with normal CTG group with no adverse perinatal outcome.
* Tel.: +0096633463859. E-mail address: [email protected] Peer review under responsibility of Middle East Fertility Society.
Production and hosting by Elsevier 1110-5690 Ó 2012 Production and hosting by Elsevier B.V. on behalf of Middle East Fertility Society. http://dx.doi.org/10.1016/j.mefs.2012.11.004
Could adverse perinatal outcome be predicted from intrapartum
269
Conclusion: UV Doppler study in combination with CTG monitoring as a part of the intra partum fetal surveillance in low risk pregnancy might give additional useful information about fetal condition and suspected intrapartum fetal hypoxia. Ó 2012 Production and hosting by Elsevier B.V. on behalf of Middle East Fertility Society.
1. Introduction Intrapartum fetal monitoring for the detection of fetal hypoxia currently includes cardiotocography (CTG), ST-analysis of the fetal ECG (STAN), fetal scalp blood sampling and fetal pulse oxymetry. CTG reduced the risk of hypoxic injury to the fetus at the cost of an increased rate of intrapartum Cesarean section, furthermore, it requires experience for an interpretation with both false-positive as well as false-negative results (1). Although STAN reduces the rate of emergency Cesarean delivery for fetal distress and metabolic acidosis, it is not available at all centers (2). Fetal scalp blood sampling for pH provides additional information about the fetal condition, however the sample can be difficult to obtain with only momentary information about the fetal condition and repeated samplings might therefore be necessary (3). Doppler velocimetry of the umbilical circulation has become a valuable tool for detecting the hemodynamic alterations that occur in response to fetal hypoxia (4). Previously the only markers of an adverse perinatal outcome were a decrease in, or cessation of, end diastolic flow, and the presence of umbilical vein pulsations in the free floating loop of the umbilical cord (5). More recently, many authors have used UA flow patterns as markers of fetal well-being to provide information about the feto-placental circulation (6). While most studies reported concern about alterations of the UA Doppler indices throughout pregnancy, few are being performed during the active phase of labor (7,8). Umbilical venous blood flow could be considered a more direct and physiological measurement of placental vascular function than umbilical artery Doppler indices as it represents indirectly the quantity of oxygen and nutrients reaching the fetus (9). Under physiological conditions Doppler examination of the UV will show an even, non pulsating blood flow velocity pattern (6). UV pulsations are normal findings in early pregnancy due to the small diameter of the vessel, and these pulsations disappear at around 13 weeks of gestation (7). In chronic hypoxia, as a result either dilatation of the ductus venosus or myocardial decompensation and increased central venous pressure pulsations in the UV could be seen (9–11). UV pulsations could also be a sign of fetal heart failure in non-immune hydropic fetuses (12), and are common findings in fetal chromosomal anomalies (13). The purpose of this study was to evaluate the value of umbilical artery and umbilical vein Doppler study to predict adverse perinatal events in low risk women with abnormal cardiotocography. 2. Patients and methods This prospective short study was conducted on 66 patients admitted to the Royal Commission Hospital, El Gubail Industrial City, Saudi Arabia, between January 2010 and April 2012.
Inclusion criteria were: (1) singleton pregnancy, (2) gestational age between 37 and 42 weeks according to the reliable date of LMP and early ultrasound examination, (3) cephalic presentation in the active phase of labor defined as cervical dilation more than 3 cm with active regular uterine contractions, (4) absence of maternal disease or congenital fetal anomalies and (5) intact membrane at time of evaluation. Exclusion criteria were (1) second stage of labor; (2) the need for immediate intervention; (3) difficult or incomplete Doppler examination; (4) patients with risk factor for perinatal asphexia as cardiac, hypertensive patients were also excluded. Informed consent was taken from all participants and the study was approved by the local hospital ethics and research committee. Cardiotocography (CTG) was done on admission and the cases were classified accordingly into two groups: (group 1) includes (33) cases with normal CTG findings, (group 2) includes (33) cases with pathological CTG findings. CTG was considered pathological if there are repeated late decelerations, repeated variable decelerations with duration >60 s, and fetal tachycardia >180 bpm with pathological variability <5or >25 bpm. Color Doppler examination was performed by an examiner blinded to CTG results .Both UA and UV were examined using (GE healthcare, Voluson 730 pro V, Austria) medical system equipped with a 3.75-MHz abdominal transducer. The UA was examined in a free-floating loop of the cord and the UV was examined in the middle portion of its intraabdominal part between the abdominal wall and the ductus venosus and in the free floating loop of the cord. Recordings were performed in the woman in supine position in between uterine contractions, and in the absence of maternal and fetal movements. The presence or absence of pulsations in the UV blood velocity wave form was noted and indices of UA; Systolic/diastolic ratio S/D ratio, resistance index RI, pulsatility index PI, and the flow velocity integral (FVI) were calculated. The obstetrician who attends the delivery was blinded to the results of Doppler examination. The following data were recorded: degree of cervical dilation, condition of the membranes, presence of meconium stained amniotic fluid, mode of delivery and examination to delivery interval were recorded as well as rate of emergency delivery (Cesarean section, forceps, ventose) for fetal distress. At delivery cord blood samples were taken from both UA and UV pH analyses. Postnatal gross examination of the cord was performed to reveal any abnormalities such as hypocoiling or true knotting. The primary outcomes of this study were emergency Cesarean deliveries for suspected fetal distress Apgar score at 1 and 5 min, UA and UV cord blood pH, and the need for neonatal intensive care unit (NICU) admission. The secondary outcomes were fetal birth weight, presence of small gestational age (SGA) fetuses (defined as birth weight 6 2 SD of mean birth weight for gestational age), and meconium stained amniotic fluid.
270
E.M. Kamal
Student´s t test and Fisher’s exact test were used for statistical analysis, as appropriate. All data were managed and analyzed using a statistical package for Windows (Statistica). A probability value of <0.05 was considered statistically significant. 3. Results Five cases were excluded as immediate intervention was required, 2 cases were in the second stage of labor, and 3 cases were with inadequate Doppler examination of intra abdominal part of UV because of Doppler beam obstruction by fetal limbs. Doppler examinations were difficult in 5 cases with ruptured membrane. Table 1 shows a comparison of clinical and Doppler characteristics between the groups with and without pathological CTG. Ruptured membranes, oxytocin infusion, and shorter examination to delivery were significantly common in pathological than in normal CTG group. High UA Doppler indices were found in 2 (6.1%) cases in the path CTG group and in no case in the normal CTG group. No UV pulsations in floating loop of the cord were seen in either group. Pulsa-
Table 1
tions in the intra abdominal part of the UV were present in 13 (39.4%) cases in the path CTG group and were absent in the normal CTG group. Comparison of perinatal outcome between the two groups with normal and pathological CTG is shown in Table 2. Meconium stained amniotic fluid was significantly higher in pathological than in normal CTG group 54.5% vs. 6.2% respectively (P < 0.05). In the normal CTG group SVD occurred in 30 (90.9%) cases, 2 cases underwent cesarean section and one case delivered by vacuum extraction for prolonged labor with no emergency delivery for fetal distress. In the path CTG group SVD occurred in only 13 (39.3%) cases, and 16 (48.4%) of cases were of emergency delivery for fetal distress (14 cases by CS and 2 cases by vacuum extraction, and the last 4 cases underwent operative delivery for prolonged labor (3 cases CS and one case vacuum extraction). No significant difference was found between the two groups regarding fetal weight, 5 min APGAR score, umbilical artery or vein cord blood pH, or NICU admission (Table 2). Regarding the type of CTG abnormality 15 cases presented with late decelerations, 12 cases with repeated variable decelerations, and 6 cases with fetal tachycardia >180 bpm with pathological variability <5 or >25 bpm.
Clinical and Doppler characteristics in the two studied groups.
Parameter
Normal CTG n = 33
Path CTG n = 33
t
P
Maternal age (Mean ± SD)
26.5 ± 4.9
26.1 ± 5.4
0.05
0.96
Parity Nulliparous Multipara Gestational age (weeks) Cervical dilation (cm) (Mean ± SD) Examination to delivery interval(min) Ruptured membranes Oxytocin infusion Pulsations of intra abdominal part of UV UV pulsation in free floating loop of umbilical cord High Doppler indices of UA
18 (54.5) 15 (45.5) 39.1 ± 1.3 5.7 ± 1.79 226.2 ± 156 19 (57.5) 6 (18.2) 0 (0.0) 0 (0.0) 0 (0.0)
20 (60.6) 13 (39.4) 39.6 ± 1.4 5.55 ± 1.48 142.2 ± 90.6 27 (81.8) 3 (9.1) 13 (39.4) 0 (0.0) 2 (6.1)
0.25 0.32 1.44 0.37 2.66 4.59a 1.7 16.1 – 0.57a
0.62 0.64 0.15 0.71 0.01* 0.02* 0.05* 0.003** – 0.49a
a
Fisher’s exact test. Significant (P = 0.05). ** Highly significant (P < 0.005). *
Table 2
Comparison of perinatal outcome between the two groups with normal and pathological CTG. Normal CTG n = 33
Path CTG n = 33
t
P
Meconium stained AF
2 (6.1)
18 (54.5)
18.3
0.05*
Mode of delivery SVD
30 (90.9)
13 (39.3)
19.2
0.05*
Emergency delivery for fetal distress CS Fetal weight in kg (Mean ± SD) 5 min Apgar score <7 UA pH < 7.1 UV pH < 7.2 N ICU admission
0 (0.0) 3.43 ± 0.4 0 (0.0) 0(0.0) 0(0.0) 1(3.0)
16 (48.4) 3.51 ± 0.44 4 (12.1) 4(12.1) 6(18.2) 3(9.1)
21.1 0.84 0.72a 0.65a 0.47a 0.45a
0.05* 0.40 0.11a 0.11a 0.02a 0.61a
a *
Fisher’s exact test. Significant (P = 0.05).
Could adverse perinatal outcome be predicted from intrapartum Table 3
271
Comparison between cases with and without UV pulsations in the pathological CTG group. No UV pulsations n = 20
UV pulsations n = 13
t
P
Ruptured membranes Meconium stained AF
15 (75.0) 7 (35.0)
12 (92.3) 11 (84.6)
0.76 7.82
0.36 0.005*
Mode of delivery SVD
12 (60.0)
1 (7.7)
9.3
0.002**
13 (92.3) 3 (23.1) 3 (23.1) 5 (38.4) 2 (15.3)
16.5 0.87a 0.56a 0.47a 0.66a
0.003** 0.27a 0.27a 0.01* 0.54a
Emergency delivery for fetal distress CS 3 (20.0) 5 min Apgar score < 7 1 (5.0) UA pH < 7.1 1 (5.0) UV pH < 7.2 1 (5.0) N ICU admission 1 (5.0) a
Fisher’s exact test. Significant (P < 0.05). ** Highly significant (P < 0.005). *
Within the group with path CTG, comparisons between cases with and without UV pulsations are shown in (Table 3), cases with UV pulsations showed significantly higher percentage of second to third degree meconium stained AF (84.6%), emergency delivery for fetal distress (92.3%), and low UV cord blood pH <7.29 (38.4%) compared to (35%), (20%), and (5%) respectively in cases without UV pulsation. Although the 5 min APGAR score <7, pH of UA <7.1, and N ICU admission were higher in cases with than those without UV pulsations, the difference was not statistically significant. 4. Discussion Intrapartum Doppler study of the umbilical vessels has been the subject of debate in the existing literature. While some studies found that the brain sparing effect did not affect umbilical circulation, and did not provide an early warning of developing fetal hypoxic acidosis (14–16), others suggested that umbilical vascular tone changes more slowly in response to hypoxia than its cerebral counterpart and observed alterations in UA Doppler velocimetry indices during labor-induced fetal hypoxia (17,18). In this study the UA Doppler indices did not show statistically significant differences between the normal and pathological CTG groups, running in agreement with previous studies that found no significant reduction in umbilical flow velocity during fetal hypoxemia and concluded that intra partum UA Doppler is a poor predictor of adverse perinatal outcome (14–16). A higher frequency of ruptured membrane, meconium staining of the amniotic fluid, and shorter examination to delivery interval were more common in cases with pathological CTG than in those with normal CTG tracing, all are expected findings and are considered a sign of fetal distress or may be due to early interference and increased rate of emergency delivery for fetal distress in this group. Under normal conditions 20–30% of the umbilical vein blood bypasses the liver and is shunted through the ductus venosus to supply the fetal heart and brain (1,2). In cases of chronic hypoxia, the ductus venosus dilates and the blood volume shunted through the ductus venosus increases to maintain adequate oxygenation of these vital organs (7–10). Therefore, the ductus venosus’ diastolic blood flow velocity waveform is
the first parameter to be affected by fetal hypoxia followed by pulsations in the intra abdominal part of the UV and lastly pulsations in the umbilical cord. We did not detect UV pulsations in the free loop of the cord in any case, a probable explanation is that a pulsating blood flow pattern in the intraabdominal part of the UV might be an early compensatory mechanism reflecting the effect of hypoxia either on the heart, ductus venosus or both, while UV pulsation in the cord only occurs in most severe cases. Although ductus venosus Doppler examination might reflect the fetal condition more accurately, we did not include it in our study because its small caliber makes examination difficult especially for patients in active labor, besides it is more sensitive to fetal and maternal movements .In addition our cases had a limited time for examination due to the severity of abnormal CTG findings. In this study we selected our cases from patients of low risk pregnancy and no cases had SGA, malformed babies or hydrops fetalis, thus the risk of chronic hypoxia or heart failure as explanation for the pulsations in UV has been kept to minimum. We detect UV pulsations in 13 (39.4%) of cases with a pathological CTG pattern in agreement with a previous study that detects UV pulsations in 27% of fetuses who later delivered by emergency Cesarean section due to changes in the CTG (19). SVD occurs more often in cases with normal CTG and those with absent UV pulsations than in cases with pathological CTG and cases with UV pulsations. Thus absence of UV pulsations as well as normal CTG tracing could be a reassuring sign. The rate of emergency delivery for fetal distress was significantly higher in cases with pathological CTG and more specifically in cases with UV pulsations. Our results agree with Ghosh et al. (20) who performed a study on 26 patients with pathological CTG, another 26 with normal CTG and found among the fetuses with pathological CTG, there was an increased risk of operative delivery for fetal distress (ODFD) in fetuses with vs. those without pulsations in the UV (P <0.0001. In addition, no pulsations were seen in the UV in the fetuses with normal CTG and these were all delivered without ODFD. Also, cases with UV pulsations within the pathological CTG group showed significantly higher UV cord blood
272 pH < 7.2 than cases without umbilical vein pulsations. In contrast to Ghosh et al. who showed an insignificant difference in higher UV cord blood pH < 7.2 in cases with and without UV pulsation (20). A probable explanation is that they included only 52 patients in their study and our sample size was larger with 66 patients. UV blood velocity recording was easy to perform, even during labor, it is worthy of mention however that Doppler examination of UV gives information about a compensatory mechanism in the fetal circulation, and it is not a direct measure of oxygen level in the fetal blood. Because the fetal condition could deteriorate rapidly after first examination, a normal Doppler examination must be repeated in relation to other parameters of fetal monitoring. In conclusion we suggest that the combined use of CTG monitoring with UV Doppler as part of the intrapartum fetal surveillance in low risk pregnancy might give additional useful information about fetal condition and suspected intrapartum fetal hypoxia. Disclosure of interests None. References (1) Thacker SB, Stroup DF, Peterson HB. Efficacy and safety of intrapartum electronic fetal monitoring: an update. Obstet Gynecol 1995;86:613–20. (2) Amer-Wahlin I, Hellsten C, Nor´ en H, Hagberg H, Herbst A, Kjellmer I, Lilja H, Lindoff C, Ma˚nsson M, Ma˚rtensson L, Olofsson P, Sundstro¨m AK, Marsal K. Cardiotocography only versus cardiotocography plus ST analysis of fetal electrocardiogram for intrapartum fetal monitoring: a Swedish randomized controlled trial. Lancet 2001;358:534–8. (3) Westgate J, Greene KR. How well is fetal blood sampling used in clinical practise? Br J Obstet Gynaecol 1994;101:250–1. (4) Campbell S, Vyas S, Nicolaides KH. Doppler investigation of the fetal circulation. J Perinat Med 1991;19:21–6. (5) Indik JH, Chen V, Reed KL. Association of umbilical venous with inferior vena cava blood flow velocities. Obstet Gynaecol 1991;77:551–7.
E.M. Kamal (6) Divon MY, Ferber A. Umbilical artery Doppler velocimetry––an update. Semin Perinatol 2001;25:44–7. (7) Siristatidis C, Salamalekis E, Kassanos D, Loghis C, Creatsas G. Evaluation of fetal intrapartum hypoxia by middle cerebral and umbilical artery Doppler velocimetry with simultaneous cardiotocography and pulse oximetry. Arch Obstet Gynecol 2004;270:265–70. (8) Eslamian L, Tooba K. Doppler findings in intrapartum fetal distress. Acta Med Iran 2011;49(8):547–50 [ISSN: 1735-9694]. (9) Figueras S, Ferna´ndez E, Herna´ndez-Andrade E, Grataco´s E. Umbilical venous blood flow measurement: accuracy and reproducibility. Ultrasound Obstet Gynecol 2008;32(4):587–91. (10) Kiserud T. Fetal venous circulation–an update on hemodynamics. J Perinat Med 2000;28:90–6. (11) Rizzo G, Arduini D, Romanini C. Umbilical vein pulsations: a physiological finding in early gestation. Am J Obstet Gynecol 1992;167:675–7. (12) Gudmundsson S, Gunnarsson GO¨, Ho¨kega˚rd KH, Ingemarsson J, Kjellmer I. Venous Doppler velocimetry in relationship to central venous pressure and heart rate during hypoxia in the ovine fetus. J Perinat Med 1999;27:81–90. (13) Bathiyar MO, Copel J. Cardiac changes in the intrauterine growth-restricted fetus. Semin Perinatol 2008;32:190–3. (14) Sutterlin MW, Seelbach-Gobel B, Oehler MK, Heupel M, Dietl J. Doppler ultrasonographic evidence of intrapartum brain-sparing effect in fetuses with low oxygen saturation according to pulse oximetry. Am J Obstet Gynecol 1999;181:216–20. (15) Malcus P, Gudmundsson S, Marsal K, Kwok HH, Vengadasalam Ratnam SS. Umbilical artery Doppler velocimetry as a labor admission test. Obstet Gynecol 1991;77:10–6. (16) Farrell T, Chien P, Gordon A. Intrapartum umbilical artery Doppler velocimetry as a predictor of adverse perinatal outcome: a systematic review. Br J Obstet Gynaecol 1999;106:783–92. (17) Kunzel W. Fetal shock syndrome. Z Geburtshilfe Perinatol 1986;190:177–84. (18) Siristatidis C, Salamalekis E, Kassanos D, Creatsas G. Alterations in Doppler velocimetry indices of the umbilical artery during fetal hypoxia in labor, in relation to cardiotocography and fetal pulse oximetry findings. Arch Obstet Gynecol 2005;272:191–6. (19) Lingman G, Laurin J, Marsal K. Circulatory changes in fetuse with imminent asphyxia. Biol Neonate 1986;49:66–73. (20) Ghosh GS, Fu J, Olofsson P, Gudmundsson S. Pulsation in the umbilical vein during labour are associated with increased risk of operative delivery for fetal distress. Ultrasound Obstet Gynecol 2009;34(2):177–81.
Middle East Fertility Society
Middle East Fertility Society Journal www.mefsjournal.org www.sciencedirect.com
ORIGINAL ARTICLE
Could adverse perinatal outcome be predicted from intrapartum umbilical vessels Doppler in women with abnormal cardiotocography? Ebtesam Moustafa Kamal
*
Obstetrics & Gynecology Departments, Faculty of Medicine, Zagazig University Egypt Received 4 September 2012; accepted 12 November 2012 Available online 30 January 2013
KEYWORDS Intra partum Doppler; Cardiotocography; Umbilical vessels; Fetal distress
Abstract Objectives: To evaluate the value of umbilical artery and umbilical vein Doppler study in predicting adverse perinatal events in low risk women with abnormal cardiotocography during labor. Design: Prospective cohort study. Setting: Emergency unit of obstetrics & gynecology department, Royal Commission hospital, El Gubail Industrial City, Saudi Arabia. Population: Sixty-six women with uncomplicated pregnancy were classified according to cardiotocography (CTG) findings during the active phase of labor into, 33 cases with normal CTG (group 1) and 33 cases with pathological CTG (group 2). Colour Doppler study of the umbilical artery (UA) and umbilical vein (UV) were performed for both groups and the results were correlated to perinatal outcome. Main outcome measures: Meconium stained amniotic fluid, emergency Cesarean deliveries for suspected fetal distress. Apgar score at 1 and 5 min, UA and UV cord blood pH, and the need for neonatal intensive care unit (NICU) admission. Results: In the pathological CTG group two (6.1%) cases had high UA Doppler indices with no adverse perinatal outcome, while 13 (39.4%) cases showed UV pulsations of them 12 (92.3%) cases underwent emergency cesarean section for fetal distress, 5 (38.4%) cases delivered babies with UV pH < 7.2. Normal UA Doppler indices and no UV pulsations were seen in all cases with normal CTG group with no adverse perinatal outcome.
* Tel.: +0096633463859. E-mail address: [email protected] Peer review under responsibility of Middle East Fertility Society.
Production and hosting by Elsevier 1110-5690 Ó 2012 Production and hosting by Elsevier B.V. on behalf of Middle East Fertility Society. http://dx.doi.org/10.1016/j.mefs.2012.11.004
Could adverse perinatal outcome be predicted from intrapartum
269
Conclusion: UV Doppler study in combination with CTG monitoring as a part of the intra partum fetal surveillance in low risk pregnancy might give additional useful information about fetal condition and suspected intrapartum fetal hypoxia. Ó 2012 Production and hosting by Elsevier B.V. on behalf of Middle East Fertility Society.
1. Introduction Intrapartum fetal monitoring for the detection of fetal hypoxia currently includes cardiotocography (CTG), ST-analysis of the fetal ECG (STAN), fetal scalp blood sampling and fetal pulse oxymetry. CTG reduced the risk of hypoxic injury to the fetus at the cost of an increased rate of intrapartum Cesarean section, furthermore, it requires experience for an interpretation with both false-positive as well as false-negative results (1). Although STAN reduces the rate of emergency Cesarean delivery for fetal distress and metabolic acidosis, it is not available at all centers (2). Fetal scalp blood sampling for pH provides additional information about the fetal condition, however the sample can be difficult to obtain with only momentary information about the fetal condition and repeated samplings might therefore be necessary (3). Doppler velocimetry of the umbilical circulation has become a valuable tool for detecting the hemodynamic alterations that occur in response to fetal hypoxia (4). Previously the only markers of an adverse perinatal outcome were a decrease in, or cessation of, end diastolic flow, and the presence of umbilical vein pulsations in the free floating loop of the umbilical cord (5). More recently, many authors have used UA flow patterns as markers of fetal well-being to provide information about the feto-placental circulation (6). While most studies reported concern about alterations of the UA Doppler indices throughout pregnancy, few are being performed during the active phase of labor (7,8). Umbilical venous blood flow could be considered a more direct and physiological measurement of placental vascular function than umbilical artery Doppler indices as it represents indirectly the quantity of oxygen and nutrients reaching the fetus (9). Under physiological conditions Doppler examination of the UV will show an even, non pulsating blood flow velocity pattern (6). UV pulsations are normal findings in early pregnancy due to the small diameter of the vessel, and these pulsations disappear at around 13 weeks of gestation (7). In chronic hypoxia, as a result either dilatation of the ductus venosus or myocardial decompensation and increased central venous pressure pulsations in the UV could be seen (9–11). UV pulsations could also be a sign of fetal heart failure in non-immune hydropic fetuses (12), and are common findings in fetal chromosomal anomalies (13). The purpose of this study was to evaluate the value of umbilical artery and umbilical vein Doppler study to predict adverse perinatal events in low risk women with abnormal cardiotocography. 2. Patients and methods This prospective short study was conducted on 66 patients admitted to the Royal Commission Hospital, El Gubail Industrial City, Saudi Arabia, between January 2010 and April 2012.
Inclusion criteria were: (1) singleton pregnancy, (2) gestational age between 37 and 42 weeks according to the reliable date of LMP and early ultrasound examination, (3) cephalic presentation in the active phase of labor defined as cervical dilation more than 3 cm with active regular uterine contractions, (4) absence of maternal disease or congenital fetal anomalies and (5) intact membrane at time of evaluation. Exclusion criteria were (1) second stage of labor; (2) the need for immediate intervention; (3) difficult or incomplete Doppler examination; (4) patients with risk factor for perinatal asphexia as cardiac, hypertensive patients were also excluded. Informed consent was taken from all participants and the study was approved by the local hospital ethics and research committee. Cardiotocography (CTG) was done on admission and the cases were classified accordingly into two groups: (group 1) includes (33) cases with normal CTG findings, (group 2) includes (33) cases with pathological CTG findings. CTG was considered pathological if there are repeated late decelerations, repeated variable decelerations with duration >60 s, and fetal tachycardia >180 bpm with pathological variability <5or >25 bpm. Color Doppler examination was performed by an examiner blinded to CTG results .Both UA and UV were examined using (GE healthcare, Voluson 730 pro V, Austria) medical system equipped with a 3.75-MHz abdominal transducer. The UA was examined in a free-floating loop of the cord and the UV was examined in the middle portion of its intraabdominal part between the abdominal wall and the ductus venosus and in the free floating loop of the cord. Recordings were performed in the woman in supine position in between uterine contractions, and in the absence of maternal and fetal movements. The presence or absence of pulsations in the UV blood velocity wave form was noted and indices of UA; Systolic/diastolic ratio S/D ratio, resistance index RI, pulsatility index PI, and the flow velocity integral (FVI) were calculated. The obstetrician who attends the delivery was blinded to the results of Doppler examination. The following data were recorded: degree of cervical dilation, condition of the membranes, presence of meconium stained amniotic fluid, mode of delivery and examination to delivery interval were recorded as well as rate of emergency delivery (Cesarean section, forceps, ventose) for fetal distress. At delivery cord blood samples were taken from both UA and UV pH analyses. Postnatal gross examination of the cord was performed to reveal any abnormalities such as hypocoiling or true knotting. The primary outcomes of this study were emergency Cesarean deliveries for suspected fetal distress Apgar score at 1 and 5 min, UA and UV cord blood pH, and the need for neonatal intensive care unit (NICU) admission. The secondary outcomes were fetal birth weight, presence of small gestational age (SGA) fetuses (defined as birth weight 6 2 SD of mean birth weight for gestational age), and meconium stained amniotic fluid.
270
E.M. Kamal
Student´s t test and Fisher’s exact test were used for statistical analysis, as appropriate. All data were managed and analyzed using a statistical package for Windows (Statistica). A probability value of <0.05 was considered statistically significant. 3. Results Five cases were excluded as immediate intervention was required, 2 cases were in the second stage of labor, and 3 cases were with inadequate Doppler examination of intra abdominal part of UV because of Doppler beam obstruction by fetal limbs. Doppler examinations were difficult in 5 cases with ruptured membrane. Table 1 shows a comparison of clinical and Doppler characteristics between the groups with and without pathological CTG. Ruptured membranes, oxytocin infusion, and shorter examination to delivery were significantly common in pathological than in normal CTG group. High UA Doppler indices were found in 2 (6.1%) cases in the path CTG group and in no case in the normal CTG group. No UV pulsations in floating loop of the cord were seen in either group. Pulsa-
Table 1
tions in the intra abdominal part of the UV were present in 13 (39.4%) cases in the path CTG group and were absent in the normal CTG group. Comparison of perinatal outcome between the two groups with normal and pathological CTG is shown in Table 2. Meconium stained amniotic fluid was significantly higher in pathological than in normal CTG group 54.5% vs. 6.2% respectively (P < 0.05). In the normal CTG group SVD occurred in 30 (90.9%) cases, 2 cases underwent cesarean section and one case delivered by vacuum extraction for prolonged labor with no emergency delivery for fetal distress. In the path CTG group SVD occurred in only 13 (39.3%) cases, and 16 (48.4%) of cases were of emergency delivery for fetal distress (14 cases by CS and 2 cases by vacuum extraction, and the last 4 cases underwent operative delivery for prolonged labor (3 cases CS and one case vacuum extraction). No significant difference was found between the two groups regarding fetal weight, 5 min APGAR score, umbilical artery or vein cord blood pH, or NICU admission (Table 2). Regarding the type of CTG abnormality 15 cases presented with late decelerations, 12 cases with repeated variable decelerations, and 6 cases with fetal tachycardia >180 bpm with pathological variability <5 or >25 bpm.
Clinical and Doppler characteristics in the two studied groups.
Parameter
Normal CTG n = 33
Path CTG n = 33
t
P
Maternal age (Mean ± SD)
26.5 ± 4.9
26.1 ± 5.4
0.05
0.96
Parity Nulliparous Multipara Gestational age (weeks) Cervical dilation (cm) (Mean ± SD) Examination to delivery interval(min) Ruptured membranes Oxytocin infusion Pulsations of intra abdominal part of UV UV pulsation in free floating loop of umbilical cord High Doppler indices of UA
18 (54.5) 15 (45.5) 39.1 ± 1.3 5.7 ± 1.79 226.2 ± 156 19 (57.5) 6 (18.2) 0 (0.0) 0 (0.0) 0 (0.0)
20 (60.6) 13 (39.4) 39.6 ± 1.4 5.55 ± 1.48 142.2 ± 90.6 27 (81.8) 3 (9.1) 13 (39.4) 0 (0.0) 2 (6.1)
0.25 0.32 1.44 0.37 2.66 4.59a 1.7 16.1 – 0.57a
0.62 0.64 0.15 0.71 0.01* 0.02* 0.05* 0.003** – 0.49a
a
Fisher’s exact test. Significant (P = 0.05). ** Highly significant (P < 0.005). *
Table 2
Comparison of perinatal outcome between the two groups with normal and pathological CTG. Normal CTG n = 33
Path CTG n = 33
t
P
Meconium stained AF
2 (6.1)
18 (54.5)
18.3
0.05*
Mode of delivery SVD
30 (90.9)
13 (39.3)
19.2
0.05*
Emergency delivery for fetal distress CS Fetal weight in kg (Mean ± SD) 5 min Apgar score <7 UA pH < 7.1 UV pH < 7.2 N ICU admission
0 (0.0) 3.43 ± 0.4 0 (0.0) 0(0.0) 0(0.0) 1(3.0)
16 (48.4) 3.51 ± 0.44 4 (12.1) 4(12.1) 6(18.2) 3(9.1)
21.1 0.84 0.72a 0.65a 0.47a 0.45a
0.05* 0.40 0.11a 0.11a 0.02a 0.61a
a *
Fisher’s exact test. Significant (P = 0.05).
Could adverse perinatal outcome be predicted from intrapartum Table 3
271
Comparison between cases with and without UV pulsations in the pathological CTG group. No UV pulsations n = 20
UV pulsations n = 13
t
P
Ruptured membranes Meconium stained AF
15 (75.0) 7 (35.0)
12 (92.3) 11 (84.6)
0.76 7.82
0.36 0.005*
Mode of delivery SVD
12 (60.0)
1 (7.7)
9.3
0.002**
13 (92.3) 3 (23.1) 3 (23.1) 5 (38.4) 2 (15.3)
16.5 0.87a 0.56a 0.47a 0.66a
0.003** 0.27a 0.27a 0.01* 0.54a
Emergency delivery for fetal distress CS 3 (20.0) 5 min Apgar score < 7 1 (5.0) UA pH < 7.1 1 (5.0) UV pH < 7.2 1 (5.0) N ICU admission 1 (5.0) a
Fisher’s exact test. Significant (P < 0.05). ** Highly significant (P < 0.005). *
Within the group with path CTG, comparisons between cases with and without UV pulsations are shown in (Table 3), cases with UV pulsations showed significantly higher percentage of second to third degree meconium stained AF (84.6%), emergency delivery for fetal distress (92.3%), and low UV cord blood pH <7.29 (38.4%) compared to (35%), (20%), and (5%) respectively in cases without UV pulsation. Although the 5 min APGAR score <7, pH of UA <7.1, and N ICU admission were higher in cases with than those without UV pulsations, the difference was not statistically significant. 4. Discussion Intrapartum Doppler study of the umbilical vessels has been the subject of debate in the existing literature. While some studies found that the brain sparing effect did not affect umbilical circulation, and did not provide an early warning of developing fetal hypoxic acidosis (14–16), others suggested that umbilical vascular tone changes more slowly in response to hypoxia than its cerebral counterpart and observed alterations in UA Doppler velocimetry indices during labor-induced fetal hypoxia (17,18). In this study the UA Doppler indices did not show statistically significant differences between the normal and pathological CTG groups, running in agreement with previous studies that found no significant reduction in umbilical flow velocity during fetal hypoxemia and concluded that intra partum UA Doppler is a poor predictor of adverse perinatal outcome (14–16). A higher frequency of ruptured membrane, meconium staining of the amniotic fluid, and shorter examination to delivery interval were more common in cases with pathological CTG than in those with normal CTG tracing, all are expected findings and are considered a sign of fetal distress or may be due to early interference and increased rate of emergency delivery for fetal distress in this group. Under normal conditions 20–30% of the umbilical vein blood bypasses the liver and is shunted through the ductus venosus to supply the fetal heart and brain (1,2). In cases of chronic hypoxia, the ductus venosus dilates and the blood volume shunted through the ductus venosus increases to maintain adequate oxygenation of these vital organs (7–10). Therefore, the ductus venosus’ diastolic blood flow velocity waveform is
the first parameter to be affected by fetal hypoxia followed by pulsations in the intra abdominal part of the UV and lastly pulsations in the umbilical cord. We did not detect UV pulsations in the free loop of the cord in any case, a probable explanation is that a pulsating blood flow pattern in the intraabdominal part of the UV might be an early compensatory mechanism reflecting the effect of hypoxia either on the heart, ductus venosus or both, while UV pulsation in the cord only occurs in most severe cases. Although ductus venosus Doppler examination might reflect the fetal condition more accurately, we did not include it in our study because its small caliber makes examination difficult especially for patients in active labor, besides it is more sensitive to fetal and maternal movements .In addition our cases had a limited time for examination due to the severity of abnormal CTG findings. In this study we selected our cases from patients of low risk pregnancy and no cases had SGA, malformed babies or hydrops fetalis, thus the risk of chronic hypoxia or heart failure as explanation for the pulsations in UV has been kept to minimum. We detect UV pulsations in 13 (39.4%) of cases with a pathological CTG pattern in agreement with a previous study that detects UV pulsations in 27% of fetuses who later delivered by emergency Cesarean section due to changes in the CTG (19). SVD occurs more often in cases with normal CTG and those with absent UV pulsations than in cases with pathological CTG and cases with UV pulsations. Thus absence of UV pulsations as well as normal CTG tracing could be a reassuring sign. The rate of emergency delivery for fetal distress was significantly higher in cases with pathological CTG and more specifically in cases with UV pulsations. Our results agree with Ghosh et al. (20) who performed a study on 26 patients with pathological CTG, another 26 with normal CTG and found among the fetuses with pathological CTG, there was an increased risk of operative delivery for fetal distress (ODFD) in fetuses with vs. those without pulsations in the UV (P <0.0001. In addition, no pulsations were seen in the UV in the fetuses with normal CTG and these were all delivered without ODFD. Also, cases with UV pulsations within the pathological CTG group showed significantly higher UV cord blood
272 pH < 7.2 than cases without umbilical vein pulsations. In contrast to Ghosh et al. who showed an insignificant difference in higher UV cord blood pH < 7.2 in cases with and without UV pulsation (20). A probable explanation is that they included only 52 patients in their study and our sample size was larger with 66 patients. UV blood velocity recording was easy to perform, even during labor, it is worthy of mention however that Doppler examination of UV gives information about a compensatory mechanism in the fetal circulation, and it is not a direct measure of oxygen level in the fetal blood. Because the fetal condition could deteriorate rapidly after first examination, a normal Doppler examination must be repeated in relation to other parameters of fetal monitoring. In conclusion we suggest that the combined use of CTG monitoring with UV Doppler as part of the intrapartum fetal surveillance in low risk pregnancy might give additional useful information about fetal condition and suspected intrapartum fetal hypoxia. Disclosure of interests None. References (1) Thacker SB, Stroup DF, Peterson HB. Efficacy and safety of intrapartum electronic fetal monitoring: an update. Obstet Gynecol 1995;86:613–20. (2) Amer-Wahlin I, Hellsten C, Nor´ en H, Hagberg H, Herbst A, Kjellmer I, Lilja H, Lindoff C, Ma˚nsson M, Ma˚rtensson L, Olofsson P, Sundstro¨m AK, Marsal K. Cardiotocography only versus cardiotocography plus ST analysis of fetal electrocardiogram for intrapartum fetal monitoring: a Swedish randomized controlled trial. Lancet 2001;358:534–8. (3) Westgate J, Greene KR. How well is fetal blood sampling used in clinical practise? Br J Obstet Gynaecol 1994;101:250–1. (4) Campbell S, Vyas S, Nicolaides KH. Doppler investigation of the fetal circulation. J Perinat Med 1991;19:21–6. (5) Indik JH, Chen V, Reed KL. Association of umbilical venous with inferior vena cava blood flow velocities. Obstet Gynaecol 1991;77:551–7.
E.M. Kamal (6) Divon MY, Ferber A. Umbilical artery Doppler velocimetry––an update. Semin Perinatol 2001;25:44–7. (7) Siristatidis C, Salamalekis E, Kassanos D, Loghis C, Creatsas G. Evaluation of fetal intrapartum hypoxia by middle cerebral and umbilical artery Doppler velocimetry with simultaneous cardiotocography and pulse oximetry. Arch Obstet Gynecol 2004;270:265–70. (8) Eslamian L, Tooba K. Doppler findings in intrapartum fetal distress. Acta Med Iran 2011;49(8):547–50 [ISSN: 1735-9694]. (9) Figueras S, Ferna´ndez E, Herna´ndez-Andrade E, Grataco´s E. Umbilical venous blood flow measurement: accuracy and reproducibility. Ultrasound Obstet Gynecol 2008;32(4):587–91. (10) Kiserud T. Fetal venous circulation–an update on hemodynamics. J Perinat Med 2000;28:90–6. (11) Rizzo G, Arduini D, Romanini C. Umbilical vein pulsations: a physiological finding in early gestation. Am J Obstet Gynecol 1992;167:675–7. (12) Gudmundsson S, Gunnarsson GO¨, Ho¨kega˚rd KH, Ingemarsson J, Kjellmer I. Venous Doppler velocimetry in relationship to central venous pressure and heart rate during hypoxia in the ovine fetus. J Perinat Med 1999;27:81–90. (13) Bathiyar MO, Copel J. Cardiac changes in the intrauterine growth-restricted fetus. Semin Perinatol 2008;32:190–3. (14) Sutterlin MW, Seelbach-Gobel B, Oehler MK, Heupel M, Dietl J. Doppler ultrasonographic evidence of intrapartum brain-sparing effect in fetuses with low oxygen saturation according to pulse oximetry. Am J Obstet Gynecol 1999;181:216–20. (15) Malcus P, Gudmundsson S, Marsal K, Kwok HH, Vengadasalam Ratnam SS. Umbilical artery Doppler velocimetry as a labor admission test. Obstet Gynecol 1991;77:10–6. (16) Farrell T, Chien P, Gordon A. Intrapartum umbilical artery Doppler velocimetry as a predictor of adverse perinatal outcome: a systematic review. Br J Obstet Gynaecol 1999;106:783–92. (17) Kunzel W. Fetal shock syndrome. Z Geburtshilfe Perinatol 1986;190:177–84. (18) Siristatidis C, Salamalekis E, Kassanos D, Creatsas G. Alterations in Doppler velocimetry indices of the umbilical artery during fetal hypoxia in labor, in relation to cardiotocography and fetal pulse oximetry findings. Arch Obstet Gynecol 2005;272:191–6. (19) Lingman G, Laurin J, Marsal K. Circulatory changes in fetuse with imminent asphyxia. Biol Neonate 1986;49:66–73. (20) Ghosh GS, Fu J, Olofsson P, Gudmundsson S. Pulsation in the umbilical vein during labour are associated with increased risk of operative delivery for fetal distress. Ultrasound Obstet Gynecol 2009;34(2):177–81.