Faculty Bibliography

OBJECTIVES: The purpose of this study was to evaluate the gestational age at sonographic detection of placenta previa as a predictor of previa persistence until delivery in twin gestations. METHODS: A retrospective cohort of twin pregnancies with placenta previa in a single ultrasound unit was analyzed from 2005 to 2010. Pregnancies were ascertained from a database. Diagnoses were confirmed by transvaginal imaging. Previa was categorized as complete if the placenta completely covered the internal os or marginal if the inferior placental edge reached within 2 cm. Gestational ages were grouped into intervals from 15 to 35 weeks. The study outcome was placenta previa at delivery. Only twin pregnancies at 25 weeks' gestation and later were analyzed using nonparametric statistics as appropriate, with P < .05 as significant. RESULTS: Placenta previa was detected in 120 twin pregnancies in the second trimester: 32 complete and 88 marginal. Of those with placenta previa at 15 to 19, 20 to 23, 24 to 27, 28 to 31, and 32 to 35 weeks, previa persisted until delivery in 8.3%, 19.2%, 50%, 75%, and 92.5%, respectively. Only at 15- to 19- and 20- to 23-week intervals was complete previa more likely to persist than marginal previa (P < .001). CONCLUSIONS: The likelihood of placenta previa persistence in twins is dependent on the gestational age at sonographic detection. Only at earlier gestations does the type of previa affect its persistence. As gestational age advances, the likelihood of resolution of placenta previa diminishes regardless of the type noted.

To estimate the risk of preterm birth in asymptomatic women with twin pregnancies with a normal cervical length (CL) and a positive fetal fibronectin (fFN), we reviewed a retrospective cohort of twin pregnancies delivered in our practice from 2005 to 2010. Patients were screened from 22 to 32 weeks with CL and fFN at 2- to 4-week intervals. We examined 244 patients with twin pregnancies and a normal CL (>25 mm) between 22 and 32 weeks and compared outcomes based on the fFN result. Fourteen (5.7%) patients had a positive fFN and 230 (94.3%) patients had a negative fFN. Positive fFN was associated with an increased the risk of spontaneous preterm birth < 37 weeks (85.7% versus 38.3%, p = 0.001), < 35 weeks (50% versus 11.8%, p < 0.001), < 34 weeks (35.7% versus 6.9%, p < 0.001), and < 32 weeks (21.4% versus 2.2%, p < 0.001). On adjusted analysis, a positive fFN was independently associated with preterm birth < 32 weeks (odds ratio 6.8, 95% confidence interval 1.42, 32.2) and gestational age at delivery (p = 0.001). In the setting of a normal CL, a positive fFN is significantly associated with preterm birth in asymptomatic twin pregnancies. Contingency model screening of fFN in asymptomatic twin pregnancies solely based on CL evaluation may fail to identify a cohort of at-risk patients.

OBJECTIVE: To examine the effect of obesity on maternal and neonatal outcomes in women diagnosed with gestational diabetes mellitus (GDM) and managed with diet only, glyburide, or insulin. STUDY DESIGN: Women with singleton gestations enrolled for outpatient services diagnosed with GDM and without history of pregnancy-related hypertension at enrollment or in a prior pregnancy were identified in a database. Women with GDM controlled by diet only (n = 3918), glyburide (n = 873), or insulin without prior exposure to oral hypoglycemic agents (n = 2229) were included. Pregnancy outcomes were compared for obese versus nonobese women within each treatment group and also compared across treatment groups within the obese and nonobese populations. RESULTS: Within each treatment group, obesity was associated with higher rates of cesarean delivery, pregnancy-related hypertension, macrosomia, and hyperbilirubinemia (all p < 0.05). Higher rates of pregnancy-related hypertension and hyperbilirubinemia were observed in women receiving glyburide. CONCLUSION: Obesity adversely affects pregnancy outcome in women with GDM. Higher rates of pregnancy-related hypertension and hyperbilirubinemia were observed in pregnant women receiving glyburide.