<unk>  is a complication of pregnancy where the umbilical<unk>  is inserted in the fetal membranes. It is a major cause of antepartum hemorrhage that leads to loss of fetal blood and associated with high perinatal mortality. In normal pregnancies, the umbilical<unk>  inserts into the middle of the placental mass and is completely encased by the amniotic sac. The vessels are hence normally protected by Wharton's jelly, which prevents rupture during pregnancy and labor. In<unk> , the vessels of the umbilical<unk>  are improperly inserted in the chorioamniotic membrane, and hence the vessels traverse between the amnion and the chorion towards the placenta. Without Wharton's jelly protecting the vessels, the exposed vessels are susceptible to compression and rupture. The exact cause of<unk>  is unknown, although risk factors include nulliparity, the use of assisted reproductive technology, maternal obesity, and pregnancy with other placental anomalies.<unk>  is often diagnosed using an abdominal ultrasound. This is most successful in the second trimester, however Color Doppler ultrasound or transvaginal ultrasound can be used in difficult cases, such as when the placenta is located posteriorly. If the woman is diagnosed with<unk> , the pregnancy is closely monitored, especially as<unk>  is a strong risk factor for vasa previa, where the exposed vessels cross the cervix and are at high risk of rupture during membrane rupture in early labor. Management strategies for<unk>  also involve determining the presence of vasa previa.<unk>  impacts fetal development during pregnancy by impairing the development of the placenta and modifying the efficiency of placental function. This can manifest in a range of adverse perinatal outcomes, such as fetal growth restriction, placental abruption, abnormal fetal heart rate patterns, and fetal death.<unk>  affects between 0.1%-1.8% of pregnancies, though its incidence increases ten-fold in multiple pregnancies.
Velamentous cord insertion
Neural clique
Vaginal septum
Uterine septum
Fetal movement
Placental expulsion
Peritomy
Circumvallate placenta