Vasa Previa: Prenatal Diagnosis and Outcomes: Thirty‐five Cases From a Single Maternal‐Fetal Medicine Practice

Abstract

Routine ultrasound screening for vasa previa using American Institute of Ultrasound in Medicine criteria will almost universally lead to good outcomes and prevent perinatal mortality.

Detection of vasa praevia in the mid‐trimester ultrasound by Australian sonographers

“…A transvaginal ultrasound is already a well‐established standard of care to assess the cervical length and assessing for vasa praevia transvaginally has identical patient preparation and imaging technique. The only difference is the colour box is placed over the lower uterine segment and the transducer is swept longitudinally and transversely identifying fetal vessels within 20 mm of the cervical IOS (Figures , , , and ). RANZCOG recommendation 2 identifies colour and pulse wave Doppler are the most accurate means to diagnose vasa praevia .…”

A survey of opinion and practice regarding prenatal diagnosis of vasa previa among obstetricians from Australia and New Zealand

“…The lack of consensus about the definition of VP is not surprising given a lack of clarity in the literature and among international experts regarding VP. There is a wide range of definitions for VP, including exposed fetal blood vessels over the internal os or cervix; within 1 cm, 2 cm, 3 cm, or 4 cm of the internal os; close to the internal os; within the lower uterine segment in front of the fetal presenting part; or arterial vessels close to the internal os . There is currently no expert international consensus or data defining the level of risk of rupture of VP according to these varied definitions to inform the optimal cutoff.…”

“…Vasa previa is most effectively diagnosed by transvaginal ultrasound using color Doppler, which has been shown to have sensitivity, specificity, and positive and negative predictive values of 100%, 99.8%, 83%, and 100% respectively. Nevertheless, there remains controversy over the use of universal rather than targeted screening …”

“…Nevertheless, there remains controversy over the use of universal rather than targeted screening. 8 The prevalence of VP has been reported as 1 per 1600-5000 deliveries. 2,8 This low prevalence means the positive predictive value of universal screening is likely to be poor, and there is the potential to do harm through unnecessary interventions such as corticosteroid administration, hospital admission, and iatrogenic preterm cesarean delivery.…”

“…8 The prevalence of VP has been reported as 1 per 1600-5000 deliveries. 2,8 This low prevalence means the positive predictive value of universal screening is likely to be poor, and there is the potential to do harm through unnecessary interventions such as corticosteroid administration, hospital admission, and iatrogenic preterm cesarean delivery. Conversely, 17% of women with VP have no established risk factors such as velamentous cord insertion, low-lying placenta, succenturiate or bi-lobed placenta, in vitro fertilization (IVF), or multiple gestation.…”