[Vasa previa: Of the diagnosis to neonatal prognosis].

Vasa previa is a rare complication of pregnancy (1/2000 to 1/6000) with a high fetal mortality rate (75 to 100%). We will discuss two case reports of vasa previa: the first was diagnosed before labor, while the second was during delivery. In the first case, the diagnosis of vasa previa was confirmed by a transvaginal ultrasound and color doppler, while the second case involved late diagnosis during delivery and after gross examination of the placenta. Risk factors for vasa previa are: low-lying placenta, bilobed or succenturiate lobed placenta, velamentous and in vitro fertilization (IVF). Antenatal diagnosis of vasa previa is crucial because it allows for prophylactic caesarean section and prevents severe Benckiser's hemorrhage responsible for a very high neonatal mortality.