Vasa previa risk factors include velamentous insertion and which of the following?

Vasa previa risk factors include velamentous insertion and which of the following?

• A. Placenta previa
• B. Fetal macrosomia
• C. Maternal diabetes only
• D. Advanced maternal age only

Answer: (A)

Vasa previa happens when fetal blood vessels cross over the cervix inside the membranes and are not protected by Wharton’s jelly, making them highly vulnerable to rupture during membrane rupture or labor. Velamentous cord insertion already puts vessels in the path of the cervical opening, but when the placenta is also previa—implanted low over the os—the risk that these unprotected vessels lie over or near the cervix increases. In this combination, fetal vessels can traverse the os and be torn if the membranes rupture, leading to rapid fetal bleeding. That’s why placenta previa is the correct risk factor paired with velamentous insertion. The other options don’t specifically create a scenario where fetal vessels overlie the cervical os, so they aren’t considered direct risk factors for vasa previa.

Vasa previa happens when fetal blood vessels cross over the cervix inside the membranes and are not protected by Wharton’s jelly, making them highly vulnerable to rupture during membrane rupture or labor. Velamentous cord insertion already puts vessels in the path of the cervical opening, but when the placenta is also previa—implanted low over the os—the risk that these unprotected vessels lie over or near the cervix increases. In this combination, fetal vessels can traverse the os and be torn if the membranes rupture, leading to rapid fetal bleeding. That’s why placenta previa is the correct risk factor paired with velamentous insertion. The other options don’t specifically create a scenario where fetal vessels overlie the cervical os, so they aren’t considered direct risk factors for vasa previa.