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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).
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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)
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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
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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
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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 ).
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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
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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.
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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
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Summary
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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, noncommercial and educational use only
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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 MaternalFetal Medicine has neither solicited nor accepted any
commercial involvement in the development of the content
of this publication.
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