Final answer:
In complete (total) placenta previa, the placenta fully covers the cervical os, posing risks of significant antepartum hemorrhage and complications for the pregnancy, often requiring special care or surgical delivery.
Step-by-step explanation:
In cases of complete (total) placenta previa, the placenta completely covers the cervical os, which is the internal opening of the cervix to the uterus. This is a serious condition as it can lead to antepartum hemorrhage, which is profuse vaginal bleeding after week 24 of pregnancy but prior to childbirth. While the placenta normally supports the growth and development of the fetus by attaching to the fundus or posterior wall of the uterus, in cases of placenta previa, its low placement within the uterus results in growth over the cervix opening as the fetus grows, posing risks to both the mother and fetus.
Complications of Placenta Previa
Most embryos implant within the body of the uterus in an area that can support their growth and development. However, in approximately 0.5 to 1 percent of pregnancies, placenta previa can occur if the embryo implants in the inferior portion of the uterus, covering the cervical opening. This can potentially complicate the pregnancy, leading to the need for specific care and possibly surgical delivery.
The correct answer to the student's question, "What happens in complete (total) placenta previa?" is c) Placenta completely covers the cervical os.