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Predicting shoulder dystocia with clinical factors: Can we prevent disaster?
SMFM Abstracts S79 255
PREDICTING SHOULDER DYSTOCIA WITH CLINICAL FACTORS: CAN WE PREVENT DISASTER? DAVID STAMILIO1, ANTHONY ODIBO1, GEORGE MACONES1, 1University of Pennsylvania Medical Center, Obstetrics & Gynecology, Philadelphia, Pennsylvania OBJECTIVE: Although shoulder dystocia and its potentially catastrophic sequelae are associated with fetal weight, labor dysfunction and maternal morbidity, no single factor can reliably predict the outcome. We sought to develop an accurate multivariable clinical prediction rule for shoulder dystocia. STUDY DESIGN: This is a case-control study nested in a perinatal database derived cohort. We compared shoulder dystocia cases to controls for maternal disease, social habits, obstetric risks, and fetal weight using bivariate & logistic regression analyses. We developed 3 clinical prediction models based on the final explanatory regression model, and compared prediction models’ test characteristics and ROC curves. RESULTS: We identified 40 cases among 1997 patients. In unadjusted analyses, shoulder dystocia was associated with advanced maternal age (AMA), obesity, false positive glucose challenge test (FPGCT), race, smoking status, and large for gestational age (LGA; >90%) fetal size. The explanatory regression model included LGA (odds ratio = OR 17.5, 95%CI 8.9-34.2), FPGCT (OR 2.4, 95%CI 1.0-5.6), non-smoking (OR 6.5, 95%CI 0.9-49), nonwhite race (OR 2.8, 95%CI 0.9-8.4) and AMA (OR 1.8, 95%CI 0.8-4.4). Obesity & diabetes were not significant risk factors after controlling for confounding. The clinical prediction rules are displayed in the table. AMA was included only in the 5-variable model. Optimal threshold scores (see table) were determined via ROC curve analysis.
257
DOES A ‘‘VANISHING TWIN’’ AFFECT FIRST-TRIMESTER BIOCHEMISTY IN DOWN SYNDROME SCREENING? STEPHEN CHASEN1, SRIRAM C PERNI1, MLADEN PREDANIC1, ROBIN B. KALISH1, FRANK A. CHERVENAK1, 1Weill Medical College of Cornell University, Obstetrics and Gynecology, New York, New York OBJECTIVE: Our objective was to evaluate the impact of spontaneous reduction in multifetal pregnancy on first-trimester maternal serum biochemistry. STUDY DESIGN: We evaluated maternal PAPP-A and free b-hCG levels drawn between 11 and 13 6/7 weeks of gestation (fetal crown-rump length 45 mm-84 mm) on 3714 singleton euploid pregnancies without anomalies. Biochemistry was performed by NTD Laboratories and was reported as gestationalspecific Multiples of the Median (MOM) adjusted for ethnicity. Biochemical values in pregnancies in which an empty gestational sac or a nonviable embryo was visualized at the time of nuchal translucency were compared to singleton pregnancies without spontaneous reduction. Continuous data were compared using Mann-Whitney U test. Categoric data were compared using Fisher’s exact test. Linear regression analysis was performed using the log (MOM) of biochemical values as the dependent variable. RESULTS: We identified 39 cases (1.1%) of spontaneous reduction; an empty sac was present in 21 and a non-viable embryo in 18. Most cases (71.8%) were in IVF pregnancies. The median PAPP-A was not significantly different in cases with and without spontaneous reduction (1.34 MOM vs. 1.19 MOM; P = .15). The median free b-hCG levels were also similar (1.07 MOM vs. 0.97 MOM; P = .30). Linear regression did not identify a significant association between spontaneous reduction, with or without a non-viable embryo, and levels of either analyte. In categoric analysis, spontaneous reduction was associated with a higher frequency of PAPP-A >95th percentile (15.8% vs. 4.9%; P = .01) compared to other pregnancies. No association between extreme values of free b-hCG and spontaneous reduction was identified. CONCLUSION: Values of biochemical analytes were not significantly different between pregnancies with and without spontaneous reduction, though an association between high values of PAPP-A and spontaneous reduction was seen. Further study is needed to elucidate the impact on risk estimation for fetal aneuploidy in these pregnancies.
258
VAGINAL DELIVERY IN TWIN GESTATIONS; OUTCOME AND PREDICTORS OF SUCCESS MICHAL LAVEE1, RAED SALIM2, ZOHAR NACHUM2, ELIEZER SHALEV3, 1Ha’Emek Medical Center, Obstetrics and Gynecology, Afula, Israel, 2Ha’Emek Medical Center, OB/GYN, Afula, Israel, 3Rappaport Faculty of Medicine, Technion, Institute of Technology, OB/GYN, Haifa, Israel OBJECTIVE: To compare maternal and neonatal outcome of twin births according to the chosen mode of delivery. STUDY DESIGN: A retrospective review of all twin deliveries during the years 1995-2004 at Haemek Medical Center labor unit, a university affiliated hospital. Data was collected from labor room records and patient files. Parameters studied include: maternal age, parity, gestational age, maternal antepartum and puerperal complications, fetal presentations, birth weight, mode of delivery of each twin, apgar scores and cord pH. RESULTS: During the study period 40710 deliveries were noted of which 804 (1.9%) were twins. Of 804 twins, 398 (49.5%) had planned cesarean sections (PCS), and 406 (50.5%) entered a trial of labor (TOL). Maternal age and parity were similar among the groups. Neonatal outcomes did not differ between the groups. Serious puerperal complications appeared solely after PCS. Of 406 women who had TOL, 84.9% eventually delivered both twins vaginally. Vaginal delivery of both twins after TOL occurred in 91% of vertexvertex presenting twins compared with 73.7% of vertex-nonvertex presenting twins (P ! .01). There was no difference in maternal age, parity, gestational age or twin birth weights between twins who were delivered vaginally and those with failed TOL. A significantly greater percentage of antepartum maternal complications were noted among those with failed TOL (8.2% vs. 1.7%, P = .01). Number of neonates with Ph !7.0 did not differ between the groups although more neonates (2.5% vs. 0.4% P = .05) among the failed TOL had apgar score !7 at 5 minutes. CONCLUSION: Vaginal delivery appears to be safe and leads to 85% vaginal delivery of both twins regardless of second twin presentation. Noncephalic presentation of 2nd twin and maternal antepartum complications were associated with lower rate of vaginal deliveries. Information regarding probability of success and risks involved should be discussed with the patients, allowing an informed decision regarding mode of delivery.
Shoulder Dystocia Multivariable Clinical Prediction Rules
Prediction rule
(+) (ÿ) Sensitivity Specificity Predictive Predictive (%) (%) value (%) value (%)
4-variable OR-weighted (score O 4) 60 4-variable Non-weighted (score O 2) 58 5-variable Non-weighted (score O 2) 58
92 89 89
14 10 10
99 O99 99
CONCLUSION: Our multivarible models predict shoulder dystocia. However, they have only moderate sensitivity and specificity.
256
VAGINAL DELIVERY FOR FETUSES AT RISK OF ALLOIMMUNE THROMBOCYTOPENIA: IS IT SAFE? ELINE VAN DEN AKKER1, DICK OEPKES1, ANNEKE BRAND2, HUMPHREY KANHAI1, 1Leiden University Medical Center, Dept. of Obstetrics, Leiden, Netherlands, 2Leiden University Medical Center, Immunohematology, E3-Q, Leiden, Netherlands OBJECTIVE: The intrapartum management of pregnancies with neonatal alloimmune thrombocytopenia (NAITP) is controversial. The current approach is either to perform predelivery fetal blood sampling (FBS) combined with, if needed, platelet transfusion followed by a vaginal delivery, or to perform an elective cesarean section. In the last decade, we adapted our protocol for pregnancies with NAITP with a sibling with thrombocytopenia but without intracranial hemorrhage (ICH) from a minimally invasive to a completely noninvasive approach. We believe that the estimated risk of FBS of 2.8%(1) is not acceptable given the infrequent occurrence (7%) of ICH in this group (1), of which an estimated 80% already occur before labor (2). The aim of this study was to evaluate the safety of vaginal delivery in these pregnancies. STUDY DESIGN: Prospective data collection of all pregnancies complicated by NAITP referred to the Leiden University Medical Center, the national referral center for management of severe red cell and platelet alloimmunization. Mode of delivery, platelet count in cord blood and neonatal outcome was analyzed in pregnancies with NAITP with a sibling with thrombocytopenia but without ICH. All women received intravenous immunoglobulines (IVIG) from 32 to 38 weeks’ gestation. Routine head ultrasound was performed in all neonates. RESULTS: Thirty-two pregnancies with NAITP were treated with IvIG without predelivery FBS. Twenty-three women delivered vaginally. Nine cesarean sections were performed, all for obstetric reasons. Mean platelet count at delivery was 142 ! 109/l (4-252) with a severe thrombocytopenia ( 50 ! 109/l) in 5 of the cases. None of the infants showed signs of ICH or other bleeding. CONCLUSION: These results confirm earlier reports that ICH is not associated with mode of delivery, and support our noninvasive management of pregnancies with NAITP in which a vaginal delivery seems safe, even without the knowledge of a predelivery platelet count. 1. Radder CM et al. Vox Sang 2003;84:318-325. 2. Spencer JA et al. Aust NZJ Obstet Gynaecol 2001;41:45-55.
PREDICTING SHOULDER DYSTOCIA WITH CLINICAL FACTORS: CAN WE PREVENT DISASTER? DAVID STAMILIO1, ANTHONY ODIBO1, GEORGE MACONES1, 1University of Pennsylvania Medical Center, Obstetrics & Gynecology, Philadelphia, Pennsylvania OBJECTIVE: Although shoulder dystocia and its potentially catastrophic sequelae are associated with fetal weight, labor dysfunction and maternal morbidity, no single factor can reliably predict the outcome. We sought to develop an accurate multivariable clinical prediction rule for shoulder dystocia. STUDY DESIGN: This is a case-control study nested in a perinatal database derived cohort. We compared shoulder dystocia cases to controls for maternal disease, social habits, obstetric risks, and fetal weight using bivariate & logistic regression analyses. We developed 3 clinical prediction models based on the final explanatory regression model, and compared prediction models’ test characteristics and ROC curves. RESULTS: We identified 40 cases among 1997 patients. In unadjusted analyses, shoulder dystocia was associated with advanced maternal age (AMA), obesity, false positive glucose challenge test (FPGCT), race, smoking status, and large for gestational age (LGA; >90%) fetal size. The explanatory regression model included LGA (odds ratio = OR 17.5, 95%CI 8.9-34.2), FPGCT (OR 2.4, 95%CI 1.0-5.6), non-smoking (OR 6.5, 95%CI 0.9-49), nonwhite race (OR 2.8, 95%CI 0.9-8.4) and AMA (OR 1.8, 95%CI 0.8-4.4). Obesity & diabetes were not significant risk factors after controlling for confounding. The clinical prediction rules are displayed in the table. AMA was included only in the 5-variable model. Optimal threshold scores (see table) were determined via ROC curve analysis.
257
DOES A ‘‘VANISHING TWIN’’ AFFECT FIRST-TRIMESTER BIOCHEMISTY IN DOWN SYNDROME SCREENING? STEPHEN CHASEN1, SRIRAM C PERNI1, MLADEN PREDANIC1, ROBIN B. KALISH1, FRANK A. CHERVENAK1, 1Weill Medical College of Cornell University, Obstetrics and Gynecology, New York, New York OBJECTIVE: Our objective was to evaluate the impact of spontaneous reduction in multifetal pregnancy on first-trimester maternal serum biochemistry. STUDY DESIGN: We evaluated maternal PAPP-A and free b-hCG levels drawn between 11 and 13 6/7 weeks of gestation (fetal crown-rump length 45 mm-84 mm) on 3714 singleton euploid pregnancies without anomalies. Biochemistry was performed by NTD Laboratories and was reported as gestationalspecific Multiples of the Median (MOM) adjusted for ethnicity. Biochemical values in pregnancies in which an empty gestational sac or a nonviable embryo was visualized at the time of nuchal translucency were compared to singleton pregnancies without spontaneous reduction. Continuous data were compared using Mann-Whitney U test. Categoric data were compared using Fisher’s exact test. Linear regression analysis was performed using the log (MOM) of biochemical values as the dependent variable. RESULTS: We identified 39 cases (1.1%) of spontaneous reduction; an empty sac was present in 21 and a non-viable embryo in 18. Most cases (71.8%) were in IVF pregnancies. The median PAPP-A was not significantly different in cases with and without spontaneous reduction (1.34 MOM vs. 1.19 MOM; P = .15). The median free b-hCG levels were also similar (1.07 MOM vs. 0.97 MOM; P = .30). Linear regression did not identify a significant association between spontaneous reduction, with or without a non-viable embryo, and levels of either analyte. In categoric analysis, spontaneous reduction was associated with a higher frequency of PAPP-A >95th percentile (15.8% vs. 4.9%; P = .01) compared to other pregnancies. No association between extreme values of free b-hCG and spontaneous reduction was identified. CONCLUSION: Values of biochemical analytes were not significantly different between pregnancies with and without spontaneous reduction, though an association between high values of PAPP-A and spontaneous reduction was seen. Further study is needed to elucidate the impact on risk estimation for fetal aneuploidy in these pregnancies.
258
VAGINAL DELIVERY IN TWIN GESTATIONS; OUTCOME AND PREDICTORS OF SUCCESS MICHAL LAVEE1, RAED SALIM2, ZOHAR NACHUM2, ELIEZER SHALEV3, 1Ha’Emek Medical Center, Obstetrics and Gynecology, Afula, Israel, 2Ha’Emek Medical Center, OB/GYN, Afula, Israel, 3Rappaport Faculty of Medicine, Technion, Institute of Technology, OB/GYN, Haifa, Israel OBJECTIVE: To compare maternal and neonatal outcome of twin births according to the chosen mode of delivery. STUDY DESIGN: A retrospective review of all twin deliveries during the years 1995-2004 at Haemek Medical Center labor unit, a university affiliated hospital. Data was collected from labor room records and patient files. Parameters studied include: maternal age, parity, gestational age, maternal antepartum and puerperal complications, fetal presentations, birth weight, mode of delivery of each twin, apgar scores and cord pH. RESULTS: During the study period 40710 deliveries were noted of which 804 (1.9%) were twins. Of 804 twins, 398 (49.5%) had planned cesarean sections (PCS), and 406 (50.5%) entered a trial of labor (TOL). Maternal age and parity were similar among the groups. Neonatal outcomes did not differ between the groups. Serious puerperal complications appeared solely after PCS. Of 406 women who had TOL, 84.9% eventually delivered both twins vaginally. Vaginal delivery of both twins after TOL occurred in 91% of vertexvertex presenting twins compared with 73.7% of vertex-nonvertex presenting twins (P ! .01). There was no difference in maternal age, parity, gestational age or twin birth weights between twins who were delivered vaginally and those with failed TOL. A significantly greater percentage of antepartum maternal complications were noted among those with failed TOL (8.2% vs. 1.7%, P = .01). Number of neonates with Ph !7.0 did not differ between the groups although more neonates (2.5% vs. 0.4% P = .05) among the failed TOL had apgar score !7 at 5 minutes. CONCLUSION: Vaginal delivery appears to be safe and leads to 85% vaginal delivery of both twins regardless of second twin presentation. Noncephalic presentation of 2nd twin and maternal antepartum complications were associated with lower rate of vaginal deliveries. Information regarding probability of success and risks involved should be discussed with the patients, allowing an informed decision regarding mode of delivery.
Shoulder Dystocia Multivariable Clinical Prediction Rules
Prediction rule
(+) (ÿ) Sensitivity Specificity Predictive Predictive (%) (%) value (%) value (%)
4-variable OR-weighted (score O 4) 60 4-variable Non-weighted (score O 2) 58 5-variable Non-weighted (score O 2) 58
92 89 89
14 10 10
99 O99 99
CONCLUSION: Our multivarible models predict shoulder dystocia. However, they have only moderate sensitivity and specificity.
256
VAGINAL DELIVERY FOR FETUSES AT RISK OF ALLOIMMUNE THROMBOCYTOPENIA: IS IT SAFE? ELINE VAN DEN AKKER1, DICK OEPKES1, ANNEKE BRAND2, HUMPHREY KANHAI1, 1Leiden University Medical Center, Dept. of Obstetrics, Leiden, Netherlands, 2Leiden University Medical Center, Immunohematology, E3-Q, Leiden, Netherlands OBJECTIVE: The intrapartum management of pregnancies with neonatal alloimmune thrombocytopenia (NAITP) is controversial. The current approach is either to perform predelivery fetal blood sampling (FBS) combined with, if needed, platelet transfusion followed by a vaginal delivery, or to perform an elective cesarean section. In the last decade, we adapted our protocol for pregnancies with NAITP with a sibling with thrombocytopenia but without intracranial hemorrhage (ICH) from a minimally invasive to a completely noninvasive approach. We believe that the estimated risk of FBS of 2.8%(1) is not acceptable given the infrequent occurrence (7%) of ICH in this group (1), of which an estimated 80% already occur before labor (2). The aim of this study was to evaluate the safety of vaginal delivery in these pregnancies. STUDY DESIGN: Prospective data collection of all pregnancies complicated by NAITP referred to the Leiden University Medical Center, the national referral center for management of severe red cell and platelet alloimmunization. Mode of delivery, platelet count in cord blood and neonatal outcome was analyzed in pregnancies with NAITP with a sibling with thrombocytopenia but without ICH. All women received intravenous immunoglobulines (IVIG) from 32 to 38 weeks’ gestation. Routine head ultrasound was performed in all neonates. RESULTS: Thirty-two pregnancies with NAITP were treated with IvIG without predelivery FBS. Twenty-three women delivered vaginally. Nine cesarean sections were performed, all for obstetric reasons. Mean platelet count at delivery was 142 ! 109/l (4-252) with a severe thrombocytopenia ( 50 ! 109/l) in 5 of the cases. None of the infants showed signs of ICH or other bleeding. CONCLUSION: These results confirm earlier reports that ICH is not associated with mode of delivery, and support our noninvasive management of pregnancies with NAITP in which a vaginal delivery seems safe, even without the knowledge of a predelivery platelet count. 1. Radder CM et al. Vox Sang 2003;84:318-325. 2. Spencer JA et al. Aust NZJ Obstet Gynaecol 2001;41:45-55.