A condition in which the placenta grows over the opening of the cervix, occurring in about 0.5 percent of pregnancies, is called:

1. Most embryos implant in the fundus or posterior wall of the uterus, an optimal location. 2. If an embryo implants close to the internal opening of the cervix instead, the growing placenta can partially or fully cover that opening. 3. This condition is called placenta previa. 4. Ectopic pregnancy and Placental abruption are both different figures a reader might guess from memory, but neither matches the specific figure given here. 5. Placenta accreta is also incorrect for the same reason: it does not match the specific figure given here. 6. Although it affects only 0.5 percent of pregnancies, It as the leading cause of antepartum hemorrhage, distinct from ectopic pregnancy (implantation outside the uterus entirely). _Source: OpenStax Anatomy and Physiology (CC BY 4.0), Ch 28 "Development and Inheritance", p.1329 §Development of the Embryo_