Vasa Previa
Overview
Plain-Language Overview
Vasa previa is a rare but serious pregnancy condition where the baby's blood vessels run across or near the opening of the cervix. These vessels are part of the umbilical cord or placenta and are not protected by the usual cushioning of the umbilical cord or placenta tissue. This can cause the vessels to rupture during labor, leading to severe bleeding and risk to the baby's health. The condition affects the circulatory system of the fetus and can cause fetal distress or even death if not detected early. It is important to identify abnormal blood vessel placement before delivery to manage risks. Symptoms may not be obvious until labor begins, making prenatal screening crucial. The main health impact is the potential for life-threatening bleeding in the baby.
Clinical Definition
Vasa previa is defined as the presence of fetal blood vessels crossing or running in close proximity to the internal cervical os beneath the fetal presenting part. These vessels are unprotected by Wharton's jelly and are vulnerable to rupture during membrane rupture or labor. The condition typically arises from abnormal placental or cord insertion, such as a velamentous cord insertion or a succenturiate lobe of the placenta. The major clinical significance is the risk of fetal hemorrhage and exsanguination, which can lead to rapid fetal demise if not promptly recognized and managed. It is strongly associated with placenta previa, multiple gestations, and assisted reproductive technologies. Early diagnosis and planned cesarean delivery before labor onset are critical to prevent catastrophic outcomes.