SMFM Clinical Consult Series Diagnosis & Management of Vasa

PreviaSociety of Maternal Fetal Medicine with the assistance of

Rachel G. Sinkey, MD; Anthony O. Odibo, MD, MSCE;Jodi S. Dashe, MD

Published in AJOG/ November 2015

Definition Vasa previa is defined when unprotected umbillical vessels

run through the amniotic membranes, and pass over the cervix.

Two types: Type I: Velamentous cord insertion and fetal vessels that

run freely within the amniotic membranes overlying the cervix or in close proximity of it (2cm from os). (Pregnancies with Low lying placentas or resolved placenta previas are at risk).

Type II:Succenturiate lobe or multilobe placenta (bilobed) and fetal vessels connecting both lobes course over or in close proximity of cervix (2cm from os).

1/2500 deliveries Perinatal mortality rate for pregnancies

complicated by Vasa previa < 10% Risk Factors:

Velamentous cord insertion Succenturiate placental lobe/bilobed placenta 60% have history of low lying placenta or

second trimester placenta previa In vitro fertilization (increases Type I Vasa

previa to 1/250)

Incidence & Risk Factors

Diagnosis of Vasa Previa

Routine Ultrasound evaluation of lower uterine segment and placenta. Detection rate 93% and specificity 99%

Often made 18-26 weeks of gestation If diagnosed in the second trimester, 20% will

be resolved

Placental location and the relationship between the placenta and internal cervical os should be evaluated

Placental cord insertion site be documented when technically possible

Diagnosis of Vasa Previa

Diagnosis of Vasa Previa

If vasa previa is suspected, transvaginal ultrasound scans with color and pulsed Doppler should be used to facilitate the diagnosis. The diagnosis of vasa previa is confirmed if an arterial vessel is visualized over the cervix, either directly overlying the internal os or in close proximity to it, and color Doppler demonstrates a rate consistent with the fetal heart rate (Figures 2 and 3 ).

Management of Vasa Previa

Goal to prolong the pregnancy safely but in the same time to avoid complications that occur if in labor or with rupture of membranes

Reasonable to consider antenatal corticosteroids at 28-32 weeks of gestation in case the need for emergent delivery

Decision for prophylactic hospitalization should be individualized and based on : Presence or absence of symptoms (eg, preterm

contractions, vaginal bleeding) History of spontaneous preterm birth Logistics (distance from hospital) Balancing of the risks that are associated with

bedrest and activity restriction

Delivery Plan

Goal to deliver before rupture of membranes while minimizing the impact of iatrogenic prematurity.

Based on available data, planned cesarean delivery for a prenatal diagnosis of vasa previa at 34-37 weeks of gestation is reasonable.

Delivery Plan

Viable gestational age with PPROM: Cesarean delivery is recommended

Vasa previa should be suspected when vaginal bleeding is accompanied with sinusoidal pattern in FHT tracing

Delivery should occur at center capable to provide immediate neonatal transfusion, O negative blood should be available in case of severe anemic neonate

Summary

The practice of medicine continues to evolve, and individual circumstances will vary. This opinion reflects information available at the time of its submission for publication and is neither designed nor intended to establish an exclusive standard of perinatal care. This presentation is not expected to reflect the opinions of all members of the Society for Maternal-Fetal Medicine.

These slides are for personal, non-commercial and educational use only

Disclaimer

Disclosures

All authors and Committee members have files conflict of interest disclosure delineating personal, professional, and/or business interests that might be perceived as a real or potential conflict of interest in relation to this publication. Any conflicts have been resolved through a process approved by the Executive Board. The Society for Maternal-Fetal Medicine has neither solicited nor accepted any commercial involvement in the development of the content of this publication.