A. Retained placenta.
B. Adherent placenta.
C. Placenta praevia.
D. Abruptio placenta.
Placenta previa is a problem of pregnancy in which the placenta grows in the lowest part of the womb (uterus) and covers all or part of the opening to the cervix.The placenta grows during pregnancy and feeds the developing baby. The cervix is the opening to the birth canal.
During pregnancy, the placenta moves as the womb stretches and grows. It is very common for the placenta to be low in the womb in early pregnancy. But as the pregnancy continues, the placenta moves to the top of the womb. By the third trimester, the placenta should be near the top of the womb, so the cervix is open for delivery.
Sometimes, the placenta partly or completely covers the cervix. This is called a previa.
There are different forms of placenta previa:
- Marginal: The placenta is next to the cervix but does not cover the opening.
- Partial: The placenta covers part of the cervical opening.
- Complete: The placenta covers all of the cervical opening.
Placenta previa occurs in 1 out of 200 pregnancies. It is more common in women who have:
- An abnormally shaped uterus
- Had many pregnancies in the past
- Had multiple pregnancies, such as twins or triplets
- Scarring on the lining of the uterus due to a history of surgery, C-section, or abortion
- In vitro fertilization.