Recent findings on low perinatal mortality in prenatally diagnosed vasa previa

Prenatal vasa previa diagnosis is not associated with perinatal death, according to a recent study published in the American Journal of Obstetrics & Gynecology.

Vasa previa presents in pregnant patients as unprotected fetal vessels travelling through the amniotic membranes to the cervix and is associated with significant perinatal mortality when undiagnosed. Membrane rupture leads to fetal blood loss or exsanguination, with approximately 56% of cases resulting in perinatal death.

An ultrasound diagnosis of vasa previa allows the condition to be diagnosed prenatally, giving patients the opportunity to undergo a cesarean delivery before membrane rupture. This has led to significantly improved outcomes when vasa previa is diagnosed prenatally, but some studies have continued to report a small mortality among prenatally diagnosed patients.

Investigators conducted a review to determine the rate of perinatal death in prenatally diagnosed vasa previa. Studies evaluating perinatal mortality and cause of mortality in patients with vasa previa diagnosed before labor were included in the analysis.

Exclusion criteria included being a conference abstract, editorial, review article, letter, or book chapter, not being published in English, French, or Spanish, not reporting perinatal survival, not separately reporting prenatally diagnosed patients, unavailable full text, and patients receiving fetoscopic laser ablation.

Databases consulted for studies from January 1, 1987, to January 1, 2023, included PubMed, Scopus, Web of Science, and Embase. Titles and abstracts were screened by 2 independent reviewers, with a third consulted to resolve conflicts. Afterward, the process was repeated for full text screening.

Data extracted included publications year, institute, country, total number of patients, number of twin or multiple pregnancies, number of pregnancies conceived using assisted reproductive technology, stillbirth, neonatal mortality, and cause of death. Risk of bias was evaluated using the Newcastle-Ottawa Scale.

There were 113 studies containing 1297 pregnant women included in the final analysis, 88 of which were case series or reports with 130 pregnancies and 25 were cohorts with 1167 pregnancies. Of cohort study pregnancies, 10.45% were multifetal pregnancies and 24.33% were conceived using assisted reproductive technology.

Thirteen perinatal deaths were reported, including 11 neonatal deaths and 2stillbirths. Of these deaths, 6 were attributed to vasa previa and the rest to other factors. Three of the vasa previa-attributed deaths occurred in dichorionic diamniotic twin pregnancies.

In 1 of the 3 twin pregnancy deaths, the newborn died because of complications of blood loss. The other 2 perinatal deaths were stillbirths. Among the 3 perinatal deaths observed in singleton pregnancies, 1 died following emergency cesarean delivery at 31 weeks’ gestation, 1 had a mother with type 1 diabetes mellitus, and 1 experienced stillbirth at 22 weeks’ gestation.

These results indicated a 0.5% risk of perinatal death attributed to vasa previa after prenatal diagnosis. Investigators concluded patients and providers should be aware of the low risk of reducing stress among pregnant individuals and families.

Reference

Conyers S, Oyelese Y, Javinani A. Incidence and causes of perinatal death in prenatally diagnosed vasa previa: a systematic review and meta-analysis. Am J Obstet Gynecol. 2024;230(1):58-65. doi:10.1016/j.ajog.2023.06.015