Accessible Requires Authentication Published by De Gruyter May 4, 2021

Vasa previa: when antenatal diagnosis can change fetal prognosis

Miriam Sutera, Anna Garofalo ORCID logo, Eleonora Pilloni, Silvia Parisi, Maria Grazia Alemanno, Guido Menato, Andrea Sciarrone and Elsa Viora



Evaluate ultrasound diagnostic accuracy, maternal−fetal characteristics and outcomes in case of vasa previa diagnosed antenatally, postnatally or with spontaneous resolution before delivery.


Monocentric retrospective study enrolling women with antenatal or postnatal diagnosis of vasa previa at Sant’Anna Hospital in Turin from 2007 to 2018. Vasa previa were defined as fetal vessels that lay 2 cm within the uterine internal os using 2D and Color Doppler transvaginal ultrasound. Diagnosis was confirmed at delivery and on histopathological exam. Vasa previa with spontaneous resolutions were defined as fetal vessels that migrate >2 cm from uterine internal os during scheduled ultrasound follow-ups in pregnancy.


We enrolled 29 patients (incidence of 0.03%). Ultrasound antenatally diagnosed 25 vasa previa (five had a spontaneous resolution) while four were diagnosed postnatally, with an overall sensitivity of 96.2%, specificity of 100%, positive predictive value of 96.2%, and negative predictive value of 100%. Early gestational age at diagnosis is significally associate with spontaneously resolution (p 0.023; aOR 1.63; 95% IC 1.18–2.89). Nearly 93% of our patient had a risk factor for vasa previa: placenta previa at second trimester or low-lying placenta, bilobated placenta, succenturiate cotyledon, velametous cord insertion or assisted reproduction technologies.


Maternal and fetal outcomes in case of vasa previa antenatally diagnosed are significally improved. Our data support the evaluation of umbilical cord insertion during routine second trimester ultrasound and a targeted screening for vasa previa in women with risk factor: it allows identification of fetus at high risk, reducing fetal mortality in otherwise healthy newborns.

Corresponding author: Anna Garofalo, Gynecology and Obstetrics Unit, Prenatal Diagnosis Ultrasound Center, Sant’Anna Hospital, Città della Salute e della Scienza, University of Turin, Via Ventimiglia 3 Turin, Italy, E-mail:

  1. Research funding: None declared.

  2. Author contributions: All authors have accepted responsibility for the entire content of this manuscript and approved its submission.

  3. Competing interests: Authors state no conflict of interest.

  4. Informed consent: Informed consent was obtained from all individuals included in this study.

  5. Ethical approval: The local Institutional Review Board approved the study.


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Received: 2020-11-26
Accepted: 2021-04-14
Published Online: 2021-05-04
Published in Print: 2021-09-27

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