SMFM Clinical Consult Series Diagnosis & Management of Vasa Previa Society 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).

Incidence & Risk Factors 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)

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

Diagnosis of Vasa Previa 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 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.

Viable gestational age with PPROM: Cesarean delivery is recommended 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

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

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.