Final answer:
Vasa previa is a condition where fetal blood vessels cross near the internal opening of the uterus, often without maternal symptoms but may include painless vaginal bleeding. It is associated with other placental abnormalities and certain risk factors like IVF, multiple pregnancies, and past uterine surgeries.
Step-by-step explanation:
Vasa previa is a rare but potentially dangerous prenatal condition where fetal blood vessels cross or run near the internal opening of the uterus. These abnormal vessel positions can lead to vessel rupture, resulting in fetal bleeding, which is a severe complication. Typically, vasa previa has no specific maternal symptoms, but it may be associated with painless vaginal bleeding during the second or third trimester of pregnancy. This condition is often associated with other placental abnormalities such as velamentous cord insertion or a succenturiate-lobed placenta.
The maternal symptoms for this condition are not prominent, but when they occur, the most notable is the sudden onset of painless vaginal bleeding, which generally prompts an urgent medical assessment. Vasa previa is associated with risk factors including in vitro fertilization (IVF), multiple pregnancies (twins, triplets, etc.), and a previous history of cesarean delivery or surgeries involving the uterus.