Vasa previa is a rare disorder of placentation associated with a high rate of perinatal morbidity and mortality when undetected before delivery. We have evaluated the recent evidence for prenatal diagnosis and management of vasa previa.
Around 85% of cases of vasa previa have one or more identifiable risk factors including in-vitro fertilization, multiple gestations, bilobed, succenturiate or low-lying placentas, and velamentous cord insertion. The development of standardized prenatal targeted scanning protocols may improve perinatal outcomes. There is no clear consensus on the optimal surveillance strategy including the need for hospitalization, timing of corticosteroids administration and the value of transvaginal cervical length measurements. Outpatient management is possible if there is no evidence of cervical shortening on ultrasound and there are no symptoms of bleeding or uterine contractions. Recent national guidelines and expert reviews have recommended scheduled cesarean section of all asymptomatic women presenting with vasa previa between 34 and 36 weeks’ gestation.
Prenatal diagnosis of vasa previa is pivotal to prevent intrapartum fetal death. Although there is insufficient evidence to support the universal mid-gestation ultrasound screening for vasa previa, recent evidence indicates the need for standardized prenatal targeted screening protocols of pregnancies at high-risk of vasa previa.
aDepartment of Obstetrics and Gynecology, The Yitzhak Shamir Medical Center (formerly Assaf Harofeh Medical Center; affiliated with the Sackler School of Medicine), Tel-Aviv University, Zerifin, Tel-Aviv, Israel
bAcademic Department of Obstetrics and Gynaecology, EGA Institute for Women's Health, Faculty of Population Health Sciences, University College London, London, UK
Correspondence to Professor Eric Jauniaux, MD, PhD, Academic Department of Obstetrics and Gynaecology, Institute for Women's Health, University College London, 86-96 Chenies Mews, London WC1E 6HX, UK. Tel: +44 207 3908113; fax: +44 207 3908115; e-mail: firstname.lastname@example.org