Prenatal sonographic diagnosis of vasa previa: ultrasound findings and obstetric outcome in ten cases.

Objective: To assess the specificity of sonographic diagnosis of vasa previa and pregnancy outcome in sonographically diagnosed cases.

Methods: We prospectively collected cases of vasa previa diagnosed by color Doppler sonography. Delivery by elective Cesarean section after demonstration of fetal pulmonary maturity and prior to the onset of labor was recommended unless obstetric complications supervened. Data regarding maternal obstetric courses and newborn status were collected.

Results: Eleven cases of vasa previa without placenta previa were diagnosed among 33 208 women over an 8-year period. Ten patients had confirmation of the diagnosis by the delivering obstetrician and/or placental examination, giving a specificity of diagnosis of 91%. Among the 10 patients with confirmed vasa previa, two were delivered at 31.5 and 35.5 weeks' gestation prior to demonstration of lung maturity, and the remainder were delivered at 34-37.5 weeks, after lung maturity. All infants had normal Apgar scores and survived. One baby had Scimitar syndrome, which was not suspected from sonography.

Conclusions: The specificity of sonographic diagnosis of vasa previa at our center was 91%. Antenatal diagnosis permitted us to prevent the catastrophic outcomes commonly associated with vasa previa.