A: Fibroids are spherical collections of muscle tissue that grow within the wall of the uterus. We don't know what causes them, but we do know they are quite common, found in 20 to 40% of all women. Fibroids tend to grow during pregnancy, resulting from increased estrogen and blood supply to the uterus.

As tempting as it would be for your doctor to remove your fibroid during a cesarean section, this is not usually done. The uterus is quite vascular during pregnancy and this increases the risk of bleeding from a myomectomy (surgical removal of a fibroid). Also, fibroids grow in response to pregnancy hormones and will shrink considerably after the pregnancy. Most doctors prefer to wait until well after a pregnancy to reevaluate fibroids. If a myomectomy is deemed necessary, this would be a safer time to perform surgery.

Occasionally fibroids grow on the front wall of the uterus in the optimal location for the cesarean incision. In this case, it might be necessary to remove a fibroid to perform the cesarean delivery.