Vasa previa: diagnosis and management

Abstract

Vasa previa is a rare condition that is associated with a high rate of fetal or neonatal death when not diagnosed antenatally. The majority of available studies are either small, do not include antepartum data, limited to single institutions, or are biased by inclusion of patients from registries and online vasa previa support groups. The purpose of this study was to investigate the diagnostic and management strategies for this potentially catastrophic entity and to describe further maternal and placental risk factors that may aid in the establishment of a screening protocol for vasa previa. This was a retrospective multicenter descriptive study that included all pregnancies that were complicated by vasa previa that delivered between January 1, 2000, and December 31, 2012. Nine maternal fetal medicine practices and the hospitals in which they practice participated in data collection of diagnosis, treatment, and maternal-neonatal outcomes. Sixty-eight pregnancies were identified that included the diagnosis of vasa previa or "possible vasa previa" either in the ultrasound record or in the hospital record at the time of delivery. Four cases (5.8%) appeared to resolve on repeat ultrasound examination. Fifteen of the 64 cases that were suspected of having vasa previa could not be verified or were not documented at delivery. Of the remaining 49 cases, where vasa previa was documented, 47 cases (96%) were diagnosed by ultrasound scanning antenatally. Known risk factors for vasa previa were present in 41 of 47 cases (87%). Of the 49 cases, 41 were delivered by planned cesarean delivery at a mean gestational age of 34.7 weeks, and 8 cases required emergent cesarean delivery at a mean gestational age of 34.6 weeks (range, 32.4-36.0 weeks gestation). Seven of these emergent cesarean deliveries had been diagnosed previously; 1 case had not. All of the emergent cesarean deliveries were for vaginal bleeding; 1 case was also for a concerning fetal heart rate, but only 1 of the known cases had a documented ruptured fetal vessel. None of these cases were found to have cervical shortening before the onset of bleeding. One of the undiagnosed cases resulted in a ruptured fetal vessel and a baby with no heart beat at birth who survived but had periventricular leukomalacia at 1 month of age with mild white-matter atrophy. Of the remaining neonates in this group, there were no deaths and no major complications beyond mild respiratory distress syndrome in 9 cases. There were no other major neonatal complications, which included no cases of periventricular leukomalacia, neonatal sepsis, necrotizing enterocolitis, or any grade of intraventricular hemorrhage in the confirmed cases of vasa previa. This study confirms most current recommendations that include risk-based ultrasound screening, early hospitalization at 30-34 weeks gestation, antenatal corticosteroids at 30-32 weeks gestation, and elective delivery at 33-34 weeks gestation. Thus, with these recommendations for current identification and management of vasa previa in this series of geographically diverse mostly private practice maternal fetal medicine practices, we have confirmed recent reports that show a dramatic improvement in neonatal survival and complications compared with earlier reports.