Prenatally Diagnosed Vasa Previa: A Single-Institution Series of 96 Cases.

OBJECTIVE: To describe outcomes for a large cohort of women with prenatally diagnosed vasa previa, determine the percentage in patients without risk factors, and compare delivery timing and indications for singletons and twins. METHODS: This was a retrospective case series of women with prenatally diagnosed vasa previa delivered at a single tertiary center over 12 years. Potential participants were identified using hospital records and perinatal databases. Patients were included if vasa previa was confirmed at delivery and by pathologic examination. Maternal and newborn data were gathered from medical records. RESULTS: There were 77 singleton and 19 twin pregnancies with a prenatal diagnosis of vasa previa. There was one neonatal death from congenital heart disease. Perinatal management of recommended elective hospitalizations with corticosteroid administration and elective early delivery resulted in average gestational age for delivery in singletons at 34.7±1.6 weeks and 32.8±2.2 weeks for twins. Among the 77 singletons, delivery was elective in 48, as a result of contractions or labor in 21, bleeding in four, nonreassuring tracing in two, asymptomatic cervical shortening in one, and preeclampsia in one. Among 19 twins, delivery was elective in six and for contractions or labor in 13. Sixty-eight percent of twins compared with 37% of singletons had nonelective delivery (P<.05). Delivery occurred by 32 weeks of gestation in 6.4% of singletons and 26% of twins (P<.05) and by 34 weeks of gestation in 11% of singletons and 58% of twins (P<.001). Six neonates (5.2%) had major anomalies, all prenatally detected. Respiratory distress syndrome occurred in 57.1% of singletons and 65.7% of twins. Nineteen singletons (24.7%) had no risk factors for vasa previa. CONCLUSION: Planned preterm delivery for women with prenatally diagnosed vasa previa resulted in elective delivery for singletons in 62% and for twins 32%. Gestational age at birth on average was 34.7 weeks for singletons and 32.8 weeks of gestation for twins. Major anomalies were frequent as was respiratory distress syndrome. Elective delivery between 34 and 35 weeks of gestation for singletons is reasonable. As a result of the high rate of nonelective delivery in twins, delivery at 32-34 weeks of gestation may be risk-beneficial. The high rate of singletons without risk factors for vasa previa reinforces the recommendation to screen routinely for cord insertion site.