What causes placenta previa?

What is placenta previa?

Placenta previa is a condition in which the placenta is attached close to or covering the cervix (opening of the uterus). Placenta previa occurs in about one in every 200 live births. There are three types of placenta previa:

· Total placenta previa. The placenta completely covers the cervix.

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· Partial placenta previa. The placenta is partially over the cervix.

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· Marginal placenta previa. The placenta is near the edge of the cervix.

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What causes placenta previa?

The cause of placenta previa is unknown, but it is associated with certain conditions including the following:

· Women who have scarring of the uterine wall from previous pregnancies

· Women who have fibroids or other abnormalities of the uterus

· Women who have had previous uterine surgeries or cesarean deliveries

· Older mothers (over age 35)

· African-American or other minority race mothers

· Cigarette smoking

· Placenta previa in a previous pregnancy

· Being pregnant with a male fetus

Why is placenta previa a concern?

The greatest risk of placenta previa is bleeding (or hemorrhage). Bleeding often occurs as the lower part of the uterus thins during the third trimester of pregnancy in preparation for labor. This causes the area of the placenta over the cervix to bleed. The more of the placenta that covers the cervical os (the opening of the cervix), the greater the risk for bleeding. Other risks include the following:

· Abnormal implantation of the placenta

· Slowed fetal growth

· Preterm birth

· Birth defects

What are the symptoms of placenta previa?

The most common symptom of placenta previa is vaginal bleeding that is bright red and not associated with abdominal tenderness or pain, especially in the third trimester of pregnancy. However, each woman may exhibit different symptoms of the condition or symptoms may resemble other conditions or medical problems. Always consult your doctor for a diagnosis.

What is placental abruption?

Placental abruption is the premature separation of a placenta from its implantation in the uterus. Within the placenta are many blood vessels that allow the transfer of nutrients to the fetus from the mother. If the placenta begins to detach during pregnancy, there is bleeding from these vessels. The larger the area that detaches, the greater the amount of bleeding. Placental abruption occurs about once in every 100 births. It is also called abruptio placenta.

What is placenta previa?

Placenta previa is a condition in which the placenta is attached close to or covering the cervix (opening of the uterus). Placenta previa occurs in about one in every 200 live births. There are three types of placenta previa:

· Total placenta previa. The placenta completely covers the cervix.

Click Image to Enlarge

· Partial placenta previa. The placenta is partially over the cervix.

Click Image to Enlarge

· Marginal placenta previa. The placenta is near the edge of the cervix.

Click Image to Enlarge

What causes placenta previa?

The cause of placenta previa is unknown, but it is associated with certain conditions including the following:

· Women who have scarring of the uterine wall from previous pregnancies

· Women who have fibroids or other abnormalities of the uterus

· Women who have had previous uterine surgeries or cesarean deliveries

· Older mothers (over age 35)

· African-American or other minority race mothers

· Cigarette smoking

· Placenta previa in a previous pregnancy

· Being pregnant with a male fetus