Natural history of vasa previa across gestation using a screening protocol.

Abstract

OBJECTIVES:

The purpose of this study was to estimate the prevalence and persistence rate of vasa previa in at-risk pregnancies using a standardized screening protocol.

METHODS:

We conducted a descriptive study of patients with a diagnosis of vasa previa from a single ultrasound unit between June 2005 and June 2012. Vasa previa was defined as a fetal vessel within 2 cm of the internal cervical os on transvaginal sonography. Screening for vasa previa using transvaginal sonography with color flow mapping was performed routinely in the following situations: resolved placenta previa, prior pregnancy with vasa previa, velamentous insertion of the cord in the lower uterine segment, placenta succenturiata in the lower uterine segment, and twin gestations.

RESULTS:

A total of 27,573 patients were referred to our unit for fetal anatomic surveys over the study period. Thirty-one cases of vasa previa were identified, for an incidence of 1.1 per 1000 pregnancies. Twenty-nine cases had full records available for analysis. Five patients (17.2%) had migration and resolution of the vasa previa. When the diagnosis was made during the second trimester (<26 weeks), there was a 23.8% resolution rate (5 of 21); when the diagnosis was made in the third trimester, none resolved (0 of 8 cases). Of the 24 pregnancies (5 twin gestations and 19 singleton gestations) with persistent vasa previa, there was 100% perinatal survival and a median length of gestation of 35 weeks (range, 27 weeks 5 days-36 weeks 5 days). No known missed cases were identified over the study period.

CONCLUSIONS:

The use of standardized screening for vasa previa based on focused criteria was found to be effective in diagnosing vasa previa, with a 100% survival rate. Vasa previa diagnosed during the second trimester resolves in approximately 25% of cases.

• Authors: Andrei Rebarber, Cara Dolin, Nathan S Fox, Chad K Klauser, Daniel H Saltzman, Ashley S Roman
• Journal: Journal of ultrasound in medicine : official journal of the American Institute of Ultrasound in Medicine (J Ultrasound Med) Vol. 33 Issue 1 Pg. 141-7 (Jan 2014) ISSN: 1550-9613 [Electronic] England
• PMID: 24371109 (Publication Type: Journal Article)

Topics

• Adult
• Female
• Humans
• Incidence
• Male
• Mass Screening (methods, statistics & numerical data)
• Middle Aged
• Pregnancy
• Reproducibility of Results
• Risk Assessment
• Sensitivity and Specificity
• Ultrasonography, Prenatal (methods, statistics & numerical data)
• Vasa Previa (diagnostic imaging)
• Young Adult