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Fetal heart rate patterns: how much is too much?
S182 SMFM Abstracts 443
December 2003 Am J Obstet Gynecol
HIGHER RATES OF TACHYSYSTOLE AMONG PATIENTS WITH UTERINE LEIOMYOMAS EYAL SHEINER1, TAMAR BIDERMAN1, AMNON HADAR1, AMALIA LEVY2, MIRIAM KATZ1, MOSHE MAZOR1, 1Soroka University Medical Center, Ob/Gyn, Beer-Sheva, Israel 2Faculty of Health Sciences, Ben Gurion University of the Negev, Epidemiology and Health Services Evaluation, Beer-Sheva, Israel OBJECTIVE: To determine uterine and fetal heart rate (FHR) tracing patterns associated with uterine leiomyomas. STUDY DESIGN: Uterine and FHR patterns of 44 women with uterine leiomyomas were compared with 601 tracings of controls. Tracings were interpreted during the first stage of labor, using the National Institute of Child Health and Human Development Research Planning Workshop guidelines. Interobserver and intraobserver agreements were evaluated. Chi-square or Fisher exact tests were used for comparison of proportions. P < .05 was considered statistically significant. Stratified analysis, using the MantelHaenszel technique, was performed to control for confounders. RESULTS: Interobserver and intraobserver agreements of the categoric data were good, as indicated by kappa of 0.71 and 0.86 respectively. No significant differences were noted between the groups regarding FHR patterns. Patients with leiomyomas had higher rates of uterine tachysystole as compared to these without leiomyomas (odds ratio (OR) = 21.8, 95% confidence interval (CI) 7.4-65.6; p < 0.001). Controlling for oxytocin augmentation, using the Mantel Haenszel procedure, did not change the significant association between uterine leiomyomas and tachysystole (weighted OR = 8.7, 95% CI 3.6-43.1; p < 0.001). A comparison of FHR and uterine patterns is presented in the table. CONCLUSION: Uterine leiomyomas are associated with higher rates of tachysystole. The leiomyomas might reduce the synchronicity of contractions, leading to tachysystole.
445
FHR PATTERNS IN SUDDEN INFANT DEATH SYNDROME (SIDS) CYDNEY AFRIAT MENIHAN1, MAUREEN PHIPPS2, SHERRY WEITZEN3, 1 Consultant, Narragansett, RI 2Women and Infants Hospital and Brown University School of Medicine, Dept. of OB/GYN and Division of Research, Providence, RI 3Women and Infants Hospital and Brown University School of Medicine, Division of Research, Providence, RI OBJECTIVE: To determine unique patterns in electronic fetal monitoring (EFM) tracings of infants who died from SIDS. STUDY DESIGN: This case-control study of 130 infants born between 1990 and 1998 included 32 cases, identified as infants who died from SIDS, matched by date of birth to 98 control infants (3 controls per case). The diagnosis for SIDS was confirmed by autopsy. Demographic, antepartum and intrapartum data were collected from the maternal medical records. EFM records were reviewed by blinded, trained research nurses. EFM records were interpreted using standardized definitions and recognition tools. Descriptive analyses were performed on each variable and two by two tables were used to generate crude odds ratios and 95% confidence intervals (CI). RESULTS: Twenty-nine maternal charts and 22 EFM records in the SIDS group and 98 maternal charts and 77 EFM tracings in the control group were available for review. Compared with the control group, infants who subsequently died from SIDS had a lower median birth weight (SIDS 2840gm vs controls 3385gm; p < 0.01), younger mean maternal age (SIDS 22 years vs controls 28 years; p < 0.01) and less intention to breastfeed (SIDS 26% vs controls 57%; p < 0.01). Compared with controls, infants who died from SIDS were more likely to have Medicaid health insurance (OR 4.6; CI 1.9, 11.2), unmarried parents (OR 5.2; CI 2.1, 12.8), and mothers who smoked cigarettes (OR 4.6; 1.9, 11.2). Comparing EFM records, no statistical differences were noted in any measured parameter including average baseline rate or variability; accelerations, decelerations; or sleep wake cycles. CONCLUSION: There were no differences in the intrapartum EFM records between infants who subsequently died from SIDS and a control group of infants, implying that EFM is not able to detect differences in the fetal autonomic nervous system of these fetuses. (Funded by a Philips/AWHONN grant)
446
ST SEGMENT ANALYSIS OF THE FETAL ELECTROCARDIOGRAM (ECG) PLUS ELECTRONIC FETAL HEART RATE MONITORING (EFM) IN LABOR: RELATIONSHIP TO UMBILICAL CORD ARTERIAL BLOOD GASES KRISTINA DERVAITIS1, MONICA POOLE1, GAIL SCHMIDT1, DEBORAH PENEVA1, RENATO NATALE1, ROBERT GAGNON2, 1University of Western Ontario, Obstetrics & Gynecology, London, Ontario, Canada 2 University of Western Ontario, Obstetrics, Gynecology & Physiology, London, Ontario, Canada OBJECTIVE: To determine the ability of intrapartum EFM plus fetal ECG ST segment automated ANalysis (STANÒ) monitoring to predict metabolic acidemia at birth. STUDY DESIGN: A prospective validation trial using STANÒ monitor was conducted at a tertiary care center. Participants were 105 women with singleton, term pregnancies who required intrapartum monitoring with a fetal scalp electrode. Attending physicians had access only to the standard EFM tracing and were blinded to the ST analysis information. Following delivery, two trained observers blinded to neonatal outcome and ST analysis, performed visual classification of each 10 minute EFM segment using FIGO guidelines. The combination of STANÒ data and visual assessment of EFM segments were used to determine whether or not STANÒ clinical guidelines dictated intervention at any time during labor. Metabolic acidemia intervention cutoff was defined as umbilical artery pH < 7.15 with base deficit $ 12 mmol/L. RESULTS: STAN Ò clinical guidelines dictated intervention in 37 out of 105 patients (35%) and 6 (5.7%) met criteria for metabolic acidemia (pH range: 6.97-7.13). When using STANÒ clinical guidelines, our data indicated a sensitivity of 50%, specificity of 66%, negative predictive value of 96% and a positive predictive value of 8% for metabolic acidemia at birth. Poor ECG signal quality despite good EFM tracings (ECG signal loss) occurred 13% of the recording time. The mean ECG signal loss in the 3 acidemic cases in which STANÒ guidelines dictated intervention was 6.9% (range: 2-12%) compared with 28.5% (range: 11-47%) in the 3 acidemic cases in which STANÒ guidelines did not dictate intervention. CONCLUSION: The STANÒ clinical guidelines have a good negative predictive value but poor positive predictive value for onsetting fetal metabolic acidemia.
FHR and uterine patterns in patients with and without uterine leiomyomas (several tracings had more than one abnormality). Uterine leiomyomas (n = 44) Tachysystole Bradycardia Tachycardia Reduced variability Variable decelerations Late decelerations
444
10 1 2 9 16 0
(22.7%) (2.3%) (4.5%) (20.5%) (36.4%)
Controls (n = 601) 8 20 14 75 227 14
(1.3%) (3.3%) (2.3%) (12.5%) (37.8%) (2.3%)
P value < 0.001 0.573 0.299 0.129 0.852 0.368
FETAL HEART RATE PATTERNS: HOW MUCH IS TOO MUCH? EMILY F. HAMILTON1, ROBERT W. PLATT2, 1McGill University, Obstetrics and Gynecology, Montreal, Quebec, Canada 2McGill University, Biostatistics and Epidemiology, Montreal, QC, Canada OBJECTIVE: To measure the diagnostic performance of computerdetected fetal heart rate patterns STUDY DESIGN: Data from 28 term babies with hypoxic ischemic encephalopathy (HIE) with an umbilical artery base deficit over 12 mmol/L at birth were compared to measurements from 56 babies matched for gestational age, without encephalopathy and a base deficit under 8 mmol/L at birth. Computer algorithms measured 13 fetal heart rate features in the 3 hours of recording before birth. Receiver operator curves (ROC) were constructed for each feature and the area under (AU) these curves compared using a v squared test. We conducted a series of pairwise comparisons using similar tests with a Bonferroni correction for multiple testing RESULTS: The following table shows the AUC and other results for selected features. CONCLUSION: No single pattern was present in all cases of HIE or absent in all controls. Using the AU of the ROC, all patterns except accelerations have reasonable and statistically similar ability to predict HIE. This is expected when more than one physiological mechanism leads to HIE. Combining the factors improves performance however; interactions between these factors are complex. These data provide an empirical basis for choosing an intervention threshold where the consequences of a false negative and false positive are so different. It also provides a starting point to estimate the value of superimposed technologies. Results
Late decels % time in low variability No.of Variables >60 bpm Area of Variables >60 bpm No. of Lates >30 bpm Area of Lates >30 bpm
Area ROC
Threshold
0.705 0.767 0.727 0.701 0.695 0.692
any amount over 7.5% 4 or more >80,000 2 or more >15,000
False Sensitivity Positive 89.3% 42.9% 42.9% 42.9% 32.1% 25.0%
62.5% 8.9% 8.9% 7.1% 8.9% 8.9%
December 2003 Am J Obstet Gynecol
HIGHER RATES OF TACHYSYSTOLE AMONG PATIENTS WITH UTERINE LEIOMYOMAS EYAL SHEINER1, TAMAR BIDERMAN1, AMNON HADAR1, AMALIA LEVY2, MIRIAM KATZ1, MOSHE MAZOR1, 1Soroka University Medical Center, Ob/Gyn, Beer-Sheva, Israel 2Faculty of Health Sciences, Ben Gurion University of the Negev, Epidemiology and Health Services Evaluation, Beer-Sheva, Israel OBJECTIVE: To determine uterine and fetal heart rate (FHR) tracing patterns associated with uterine leiomyomas. STUDY DESIGN: Uterine and FHR patterns of 44 women with uterine leiomyomas were compared with 601 tracings of controls. Tracings were interpreted during the first stage of labor, using the National Institute of Child Health and Human Development Research Planning Workshop guidelines. Interobserver and intraobserver agreements were evaluated. Chi-square or Fisher exact tests were used for comparison of proportions. P < .05 was considered statistically significant. Stratified analysis, using the MantelHaenszel technique, was performed to control for confounders. RESULTS: Interobserver and intraobserver agreements of the categoric data were good, as indicated by kappa of 0.71 and 0.86 respectively. No significant differences were noted between the groups regarding FHR patterns. Patients with leiomyomas had higher rates of uterine tachysystole as compared to these without leiomyomas (odds ratio (OR) = 21.8, 95% confidence interval (CI) 7.4-65.6; p < 0.001). Controlling for oxytocin augmentation, using the Mantel Haenszel procedure, did not change the significant association between uterine leiomyomas and tachysystole (weighted OR = 8.7, 95% CI 3.6-43.1; p < 0.001). A comparison of FHR and uterine patterns is presented in the table. CONCLUSION: Uterine leiomyomas are associated with higher rates of tachysystole. The leiomyomas might reduce the synchronicity of contractions, leading to tachysystole.
445
FHR PATTERNS IN SUDDEN INFANT DEATH SYNDROME (SIDS) CYDNEY AFRIAT MENIHAN1, MAUREEN PHIPPS2, SHERRY WEITZEN3, 1 Consultant, Narragansett, RI 2Women and Infants Hospital and Brown University School of Medicine, Dept. of OB/GYN and Division of Research, Providence, RI 3Women and Infants Hospital and Brown University School of Medicine, Division of Research, Providence, RI OBJECTIVE: To determine unique patterns in electronic fetal monitoring (EFM) tracings of infants who died from SIDS. STUDY DESIGN: This case-control study of 130 infants born between 1990 and 1998 included 32 cases, identified as infants who died from SIDS, matched by date of birth to 98 control infants (3 controls per case). The diagnosis for SIDS was confirmed by autopsy. Demographic, antepartum and intrapartum data were collected from the maternal medical records. EFM records were reviewed by blinded, trained research nurses. EFM records were interpreted using standardized definitions and recognition tools. Descriptive analyses were performed on each variable and two by two tables were used to generate crude odds ratios and 95% confidence intervals (CI). RESULTS: Twenty-nine maternal charts and 22 EFM records in the SIDS group and 98 maternal charts and 77 EFM tracings in the control group were available for review. Compared with the control group, infants who subsequently died from SIDS had a lower median birth weight (SIDS 2840gm vs controls 3385gm; p < 0.01), younger mean maternal age (SIDS 22 years vs controls 28 years; p < 0.01) and less intention to breastfeed (SIDS 26% vs controls 57%; p < 0.01). Compared with controls, infants who died from SIDS were more likely to have Medicaid health insurance (OR 4.6; CI 1.9, 11.2), unmarried parents (OR 5.2; CI 2.1, 12.8), and mothers who smoked cigarettes (OR 4.6; 1.9, 11.2). Comparing EFM records, no statistical differences were noted in any measured parameter including average baseline rate or variability; accelerations, decelerations; or sleep wake cycles. CONCLUSION: There were no differences in the intrapartum EFM records between infants who subsequently died from SIDS and a control group of infants, implying that EFM is not able to detect differences in the fetal autonomic nervous system of these fetuses. (Funded by a Philips/AWHONN grant)
446
ST SEGMENT ANALYSIS OF THE FETAL ELECTROCARDIOGRAM (ECG) PLUS ELECTRONIC FETAL HEART RATE MONITORING (EFM) IN LABOR: RELATIONSHIP TO UMBILICAL CORD ARTERIAL BLOOD GASES KRISTINA DERVAITIS1, MONICA POOLE1, GAIL SCHMIDT1, DEBORAH PENEVA1, RENATO NATALE1, ROBERT GAGNON2, 1University of Western Ontario, Obstetrics & Gynecology, London, Ontario, Canada 2 University of Western Ontario, Obstetrics, Gynecology & Physiology, London, Ontario, Canada OBJECTIVE: To determine the ability of intrapartum EFM plus fetal ECG ST segment automated ANalysis (STANÒ) monitoring to predict metabolic acidemia at birth. STUDY DESIGN: A prospective validation trial using STANÒ monitor was conducted at a tertiary care center. Participants were 105 women with singleton, term pregnancies who required intrapartum monitoring with a fetal scalp electrode. Attending physicians had access only to the standard EFM tracing and were blinded to the ST analysis information. Following delivery, two trained observers blinded to neonatal outcome and ST analysis, performed visual classification of each 10 minute EFM segment using FIGO guidelines. The combination of STANÒ data and visual assessment of EFM segments were used to determine whether or not STANÒ clinical guidelines dictated intervention at any time during labor. Metabolic acidemia intervention cutoff was defined as umbilical artery pH < 7.15 with base deficit $ 12 mmol/L. RESULTS: STAN Ò clinical guidelines dictated intervention in 37 out of 105 patients (35%) and 6 (5.7%) met criteria for metabolic acidemia (pH range: 6.97-7.13). When using STANÒ clinical guidelines, our data indicated a sensitivity of 50%, specificity of 66%, negative predictive value of 96% and a positive predictive value of 8% for metabolic acidemia at birth. Poor ECG signal quality despite good EFM tracings (ECG signal loss) occurred 13% of the recording time. The mean ECG signal loss in the 3 acidemic cases in which STANÒ guidelines dictated intervention was 6.9% (range: 2-12%) compared with 28.5% (range: 11-47%) in the 3 acidemic cases in which STANÒ guidelines did not dictate intervention. CONCLUSION: The STANÒ clinical guidelines have a good negative predictive value but poor positive predictive value for onsetting fetal metabolic acidemia.
FHR and uterine patterns in patients with and without uterine leiomyomas (several tracings had more than one abnormality). Uterine leiomyomas (n = 44) Tachysystole Bradycardia Tachycardia Reduced variability Variable decelerations Late decelerations
444
10 1 2 9 16 0
(22.7%) (2.3%) (4.5%) (20.5%) (36.4%)
Controls (n = 601) 8 20 14 75 227 14
(1.3%) (3.3%) (2.3%) (12.5%) (37.8%) (2.3%)
P value < 0.001 0.573 0.299 0.129 0.852 0.368
FETAL HEART RATE PATTERNS: HOW MUCH IS TOO MUCH? EMILY F. HAMILTON1, ROBERT W. PLATT2, 1McGill University, Obstetrics and Gynecology, Montreal, Quebec, Canada 2McGill University, Biostatistics and Epidemiology, Montreal, QC, Canada OBJECTIVE: To measure the diagnostic performance of computerdetected fetal heart rate patterns STUDY DESIGN: Data from 28 term babies with hypoxic ischemic encephalopathy (HIE) with an umbilical artery base deficit over 12 mmol/L at birth were compared to measurements from 56 babies matched for gestational age, without encephalopathy and a base deficit under 8 mmol/L at birth. Computer algorithms measured 13 fetal heart rate features in the 3 hours of recording before birth. Receiver operator curves (ROC) were constructed for each feature and the area under (AU) these curves compared using a v squared test. We conducted a series of pairwise comparisons using similar tests with a Bonferroni correction for multiple testing RESULTS: The following table shows the AUC and other results for selected features. CONCLUSION: No single pattern was present in all cases of HIE or absent in all controls. Using the AU of the ROC, all patterns except accelerations have reasonable and statistically similar ability to predict HIE. This is expected when more than one physiological mechanism leads to HIE. Combining the factors improves performance however; interactions between these factors are complex. These data provide an empirical basis for choosing an intervention threshold where the consequences of a false negative and false positive are so different. It also provides a starting point to estimate the value of superimposed technologies. Results
Late decels % time in low variability No.of Variables >60 bpm Area of Variables >60 bpm No. of Lates >30 bpm Area of Lates >30 bpm
Area ROC
Threshold
0.705 0.767 0.727 0.701 0.695 0.692
any amount over 7.5% 4 or more >80,000 2 or more >15,000
False Sensitivity Positive 89.3% 42.9% 42.9% 42.9% 32.1% 25.0%
62.5% 8.9% 8.9% 7.1% 8.9% 8.9%