Faculty Bibliography

OBJECTIVE: We sought to assess the association between maternal height and the risk of preterm birth, fetal growth restriction and mode of delivery in twin gestations. STUDY DESIGN: Cohort study of patients with twin pregnancies delivered from 2005 to 2014. We compared pregnancy outcomes between patients of short stature /=160 cm. Patients with monoamniotic twins and major fetal anomalies were excluded. Pearson's correlation, Chi-square and Student's t-test were used as appropriate. RESULTS: Six hundred and sixty-six patients were included, 159 (23.9%) of whom had short stature (mean height 155.8 +/- 2.5 cm) and 507 (76.1%) of whom had normal stature (mean height 167.2 +/- 5.5 cm). There were no differences in outcomes between the groups in regards to preterm birth, gestational age (GA) at delivery, birth weight of either twin, preeclampsia, gestational diabetes or cesarean section rate. Results were similar when the groups were stratified by parity. As a continuous variable, maternal height did not correlate with GA at delivery (p= 0.388), cesarean delivery (p = 0.522) nor the birth weight of the larger (p = 0.206) or smaller (p = 0.307) twin. CONCLUSION: In twin pregnancies, maternal short stature is not associated with preterm birth, fetal growth restriction or cesarean section rate. This suggests that although anthropometric measurements have long been used to counsel patients in regards to outcomes, patients of short stature should be reassured that their height does not appear to lead to adverse twin pregnancy outcomes.

OBJECTIVE: To evaluate cervical pessary as an intervention to prevent preterm birth in twin pregnancies with a short cervix. METHODS: This was a retrospective cohort study of twin pregnancies managed by a single maternal-fetal medicine practice from 2005 to 2015. We included patients at 28 weeks of gestation or less who were diagnosed with a cervical length less than 20 mm. At the time of diagnosis, all patients were prescribed vaginal progesterone. Starting in 2013, they were also offered pessary placement in addition to vaginal progesterone. We compared outcomes between patients who received a pessary and matched women in a control group in a one-to-three ratio. Women in the control group were matched to women in the case group according to cervical length and gestational age (within 5 mm and 1 week, respectively, of the case patient at the time of pessary placement). We excluded patients with cerclage, monochorionic-monoamniotic placentation, major fetal congenital anomalies discovered before or after birth, patients with twin-twin transfusion syndrome, and patients for whom there were no appropriate controls. Chi-square, Fisher exact, and Student's t tests were used, as appropriate. Regression analysis was performed to control for significant differences at baseline. RESULTS: Twenty-one patients received a cervical pessary, and they were compared with 63 matched women in the control group. As expected (as a result of matching), baseline gestational age (25.7+/-2.1 compared with 25.9+/-2.1 weeks of gestation, P=.671) and cervical length (10.9+/-3.6 mm compared with 11.9+/-4.5 mm, P=.327) were similar between the groups. Patients with a pessary had a significantly lower incidence of delivery at less than 32 weeks of gestation (1/21 [4.8%] compared with 18/63 [28.6%], adjusted P=.05), longer interval to delivery (65.2+/-16.8 compared with 52.1+/-24.3 days, adjusted P=.025), and a lower incidence of severe neonatal morbidity (2/21 [9.5%] compared with 22/63 [34.9%], adjusted P=.04). CONCLUSION: For twin pregnancies with a short cervix, the addition of a cervical pessary to vaginal progesterone is associated with prolonged pregnancy and reduced risk of adverse neonatal outcomes. A large randomized trial should be performed to verify these retrospective findings.

Abstract Objective: To compare the efficacy of tocolytic treatment with indomethacin (I), magnesium sulfate (M) and nifedipine (N) for acute tocolysis in women with advanced cervical dilation (4-6 cm). Methods: A single center, randomized trial was carried out involving patients in preterm labor (cervix 1-6 cm). Secondary analysis of women with advanced cervical dilation (cervix 4-6 cm) at 24-32 weeks' gestation who received intravenous M, oral N or I suppositories comprised this study population. Results: Over 38 months, 92 women with advanced cervical dilation were randomized to one tocoloytic type. Days gained in utero (11.7) and percent remaining undelivered at 48 h (60.8%), 72 h (53.1%) and >7 days (38.3%) were similar regardless of tocolytic employed (p = 0.923, 0.968, 0.791, 0.802, respectively). Likewise, gestational age at delivery (30.7 +/- 3.2) was similar between groups (p = 0.771). Finally, neonatal statistics were not different when stratified by tocolytic treatment. Conclusion: There were no statistical differences between tocolytics in treating women with advanced cervical dilation. All offered significant days gained in utero after therapy, a high percentage remaining undelivered after 48 or 72 h and after 7 days. It would appear from data that there may be advantages to tocolytic treatment even in women with advanced cervical dilation.

OBJECTIVE: To estimate the association between glycemic control and adverse outcomes in twin pregnancies with gestational diabetes (GDM). STUDY DESIGN: A cohort of patients with twin pregnancies and GDM were identified from one maternal-fetal medicine practice from 2005 to 2014. Patients with prepregnancy diabetes were excluded. First, outcomes were compared between patients with GDMA1 and GDMA2 (gestational age at delivery, birthweight, small for gestational age (SGA, birthweight <10th percentile), preeclampsia, and cesarean delivery). Then, finger stick glucose logs were reviewed and correlated with the risk of SGA and preeclampsia. Abnormal finger stick values were defined as: fasting >/=90 mg/dL, 1-h postprandial >/=140 mg/dL, 2-h postprandial >/=120 mg/dL. RESULTS: Sixty-six patients with twin pregnancies and GDM were identified (incidence 9.1%). Comparing the 43 patients with GDMA1 to the 23 patients with GDMA2, outcomes were similar, aside from patients with GDMA1 having lower birthweight of the smaller twin (2184 +/- 519 g versus 2438 +/- 428 g, p = 0.040). The risk of preeclampsia was not associated with glycemic control. Patients with SGA had lower mean fasting values (83.3 +/- 5.5 versus 87.2 +/- 7.7 mg/dL, p = 0.033), and a lower percentage of abnormal fasting values (24.0% versus 36.9%, p = 0.040), abnormal post-breakfast values (9.9% versus 27.1%, p = 0.003), and total abnormal values (20.1% versus 27.7%, p = 0.055). CONCLUSION: In twin pregnancies with GDM, improved glycemic control is not associated with improved outcomes, and is associated with a higher risk of SGA. Prospective trials in twin pregnancies should be performed to establish goals for glycemic control in twin pregnancies.

Objective The objective of this study was to determine if first- and second-trimester biochemical markers for aneuploidy have an association with adverse pregnancy outcomes in twin gestations. Study Design A retrospective cohort study of patients who presented with dichorionic diamniotic twin gestations was performed. Patients with first-trimester low pregnancy-associated plasma protein A (PAPP-A) or low free beta human chorionic gonadotropin (beta-hCG), or second-trimester elevated alpha-fetoprotein (AFP), elevated inhibin A, elevated hCG, or low unconjugated estradiol were identified. The rates of adverse pregnancy outcomes were compared between patients with or without abnormal analytes with p < 0.05 used as significance. Results In this study, 340 pregnancies were included. Patients with a low PAPP-A had an increased risk for delivery < 37 weeks. Patients with an elevated second-trimester hCG had an increased risk for spontaneous delivery < 28 weeks and neonatal intensive care unit (NICU) admission. Patients with an elevated inhibin A had an increased risk of spontaneous delivery at < 37 and NICU admission. Patients with an elevated AFP had an increased risk of a NICU admission. Conclusion Certain abnormal aneuploidy markers are associated with an increased risk of adverse pregnancy outcomes in twin gestations.

Objectives-The nonstress test is currently the most widely used modality for antenatal surveillance in twin pregnancies, with a quoted false-positive rate of 11%-12%. Our objective was to report our experience with the sonographic portion of the biophysical profile in twin pregnancies as the primary screening modality.Methods-Women with twin pregnancies delivered by a single maternal-fetal medicine practice from 2005 to 2013 were included. We excluded monoamniotic twins. Twin pregnancies began weekly sonography for the biophysical profile starting at 32 to 33 weeks, or earlier if indicated. The nonstress test was performed if the sonographic biophysical profile score was less than 8 of 8. We reviewed biophysical profile scores and outcomes for all patients who delivered at 33 weeks or later to assess the false-positive rate for the biophysical profile, as well as the incidence of intrauterine fetal death (IUFD) after initiation of antenatal surveillance.Results-A total of 539 twin pregnancies were included. The incidence of IUFD per patient was 2 per 539 (0.4%; 95% confidence interval [CI], 0.1%-1.3%), and the incidence of IUFD per fetus was 2 per 1078 (0.19%; 95% CI, 0.05%-0.7%). The overall positive screen rate was 24 per 539 (4.45%; 95% CI, 3.0%-6.5%). The false-positive screen rate, defined as an abnormal biophysical profile that did not diagnose an IUFD or lead to delivery, was 10 per 539 (1.9%; 95% CI, 1.0%-3.4%).Conclusions-In twin pregnancies the use of the sonographic biophysical profile for routine antenatal surveillance has a low false-positive rate, with a very low incidence of IUFD. The sonographic biophysical profile should be considered as a primary mode for antenatal surveillance in twin pregnancies, with a reflex nonstress test for an abnormal score.

OBJECTIVE: Multifetal pregnancy reduction has been shown to improve outcomes in triplet and higher order multiple pregnancies. The data for fetal reduction of twin pregnancies is limited. The purpose of this study was to compare adverse pregnancy outcomes in ongoing twin pregnancies compared to twin pregnancies reduced to singletons. STUDY DESIGN: This is a retrospective cohort study comparing dichorionic diamniotic twin pregnancies with dichorionic diamniotic twin pregnancies reduced to singleton gestations between 11-24 weeks gestation in a single Maternal Fetal Medicine practice over a 9 year period. Adverse pregnancy outcomes >24 weeks were compared with p<0.05 used for significance. RESULTS: 501 ongoing twin pregnancies and 63 twin pregnancies reduced to singletons were included. Patients with reductions to singletons had a significantly lower risk of preterm delivery before 37 weeks gestation (10% vs. 43%, p<0.001) but no difference in the risk of preterm delivery before 34 weeks or 28 weeks gestation. Patients with reductions to singletons also had a lower risk of infant birth weight less than the 10% (23% vs. 49%, p<0.001), but no difference in the risk of infant birth weigh less than the 5%. There was no difference in the risk of fetal demise after 24 weeks gestation. CONCLUSION: Fetal reduction of twin pregnancies decreases the risk of late preterm birth and birth weight less than the 10% but not the risks of more severe complications such as early preterm birth or birth weight less than the 5%.

Abstract Objective: To estimate the association between maternal obesity and adverse outcomes in patients without placenta previa or accreta undergoing a tertiary or higher cesarean delivery. Study design: Retrospective cohort of patients cared for by a single MFM practice undergoing a tertiary or higher cesarean delivery from 2005 to 2013. Patients attempting vaginal delivery and patients with placenta accreta and/or placenta previa were excluded. We estimated the association of maternal obesity (prepregnancy BMI >/= 30 kg/m2) and maternal outcomes. The primary outcome was a composite of severe maternal morbidity (uterine rupture, hysterectomy, blood transfusion, cystotomy requiring repair, bowel injury requiring repair, intensive care unit admission, thrombosis, re-operation, or maternal death). Results: Three hundred and forty four patients met inclusion criteria, 73 (21.2%) of whom were obese. The composite outcome was significantly higher in the obese group (6.8% versus 1.8%, p = 0.024, aOR 4.36, 95% CI 1.21, 15.75). The incidence of several individual adverse outcomes were also increased in obese women, including blood transfusion (4.1% versus 0.7%, p = 0.033, aOR 7.36, 95% CI 1.19, 45.34), wound separation or infection (20.5% versus 5.9%, p < 0.001, aOR 4.05, 95% CI 1.75, 9.36) and 1-min Apgar score less than 7 (6.8% versus 1.9%, p = 0.024, aOR 4.40, 95% CI 1.21, 15.94). Conclusions: In patients undergoing a tertiary or higher cesarean delivery without placenta previa or accreta, obesity increases the risk of adverse outcomes. Obese patients are at risk for blood transfusion, low 1-min Apgar scores and postoperative wound complications.

OBJECTIVES: To estimate the risk of spontaneous preterm birth in twin pregnancies based on transvaginal sonographic cervical length, fetal fibronectin (fFN) testing, and the gestational age at which these tests were performed. METHODS: Women with twin pregnancies, cervical length assessment, and fFN testing between 22 weeks and 31 weeks 6 days in a single maternal-fetal medicine practice from 2005 to 2013 were included. All testing was done on asymptomatic women on an out-patient basis. Women with monochorionic monoamniotic twins and twin-twin transfusion were excluded. Logistic regression analysis was used to estimate the risk of spontaneous preterm birth before 35, 32, and 28 weeks. RESULTS: Six hundred eleven patients were included and underwent a total of 2406 cervical length measurements and 2279 fFN tests over the course of the study period. The likelihood values for spontaneous preterm birth before 35, 32, and 28 weeks were 19.1%, 6.3%, and 2.3%, respectively. The risk of spontaneous preterm birth before 35 weeks increased with a decreasing cervical length (coefficient for the log of the odds ratio [OR coefficient], -0.13; P < .01; 95% confidence interval [CI], -0.22 to -0.037), a positive fFN result (OR coefficient, 1.04; P < .01; 95% CI, 0.45 to 1.64), as well as earlier gestational ages at testing (OR coefficient, -0.214; P < .01; 95% CI, -0.33 to -0.10). Similar results were seen for spontaneous preterm birth before 32 and 28 weeks. CONCLUSIONS: In asymptomatic patients with twin pregnancies, the cervical length, fFN, and gestational age are all significantly associated with spontaneous preterm birth.