The Rate of Cervical Length Shortening in the Management of Vasa Previa.

Objectives: There is no consensus about the optimal surveillance strategy in women with a diagnosis of vasa previa. The aim of this study was to evaluate the role of the rate of change in cervical length measurements in the management of singleton pregnancies with a diagnosis of vasa previa.

Methods: We performed a retrospective case-control study of our databases for pregnancies with a prenatal diagnosis of vasa previa that were followed with transvaginal sonography for cervical length and evaluated the impact of the changes in cervical length on the need for emergency cesarean delivery.

Results: The cohort included 29 singleton pregnancies with a prenatal diagnosis of vasa previa in the second trimester. There were 14 and 15 pregnancies that underwent elective and emergency cesarean delivery, respectively. The rate of cervical length shortening was significantly slower for women with elective compared to emergency cesarean delivery (median [range], 0.7 [0.1-2.0] versus 1.5 [0.25-3.0] mm/wk; P = .011). For each additional millimeter-per-week decrease in cervical length, the odds of emergency cesarean delivery increased by 6.50 (95% confidence interval, 1.02-41.20). The receiver operating characteristic curve for the rate of cervical length shortening in the prediction of emergency cesarean delivery yielded an area under the curve of 0.85 (95% confidence interval, 0.69-0.99).

Conclusions: Our findings indicate an association between the rate of cervical length shortening and the risk of emergency cesarean delivery in pregnancies with a diagnosis of vasa previa in the second trimester. Further multicentric studies are required to validate our data prospectively and, in particular, the role of serial cervical length measurements in determining the optimal delivery time for individual cases.