A small number of pregnant women have uterine fibroids. If you are pregnant and have fibroids, they probably won't cause problems for you or your baby. During pregnancy, fibroids may increase in size. Most of this growth is due to blood flowing to the uterus. Coupled with the extra burden placed on the body by pregnancy, growth of fibroids may cause discomfort, feelings of pressure, or pain.
Fibroids usually decrease in size after pregnancy.
Rarely, a large fibroid can block the opening of the uterus, or keep the baby from passing into the birth canal. In this case, a cesarean delivery is done. Usually even a large fibroid will move up and out of the fetus's way as the uterus expands during pregnancy. Women with large fibroids may have more blood loss after delivery. Usually no treatment of fibroids is needed during pregnancy.