A fibroid tumor, which is also known as a leiomyoma, fibromyoma, or myoma, is a growth of fibrous tissue in or on the uterus. Fibroids are common, occurring in 50 to 80 percent of women and up to four percent of pregnancies. Although pregnancies with fibroids usually progress normally, fibroids can increase the chance for several pregnancy and delivery complications.
Abdominal Pain
A uterine fibroid can cause abdominal pain for a variety of reasons. With larger fibroids, the mass of the fibroid itself, in addition to the increasing fluid and size of the baby, puts pressure on the abdomen. Fibroids often grow during the first part of the pregnancy, due to increasing levels of hormones and blood supply. They may grow so fast that they do not receive sufficient oxygen from their blood supply and therefore start to break down, which can result in pain. MayoClinic.com reports that certain fibroids, called pedunculated fibroids, that grow on a stalk can sometimes twist, causing sharp pain.
Miscarriage
Fibroids that extend into the uterine cavity may cause miscarriage if they are located near where the embryo implants. According to "Fibroids: A Gynecologist's Second Opinion," fibroids may thin out the nearby lining of the uterus and cause inflammation of the tissue above them, both of which can decrease blood supply to the developing embryo. Insufficient blood supply can lead to miscarriage.
Bleeding
Uterine fibroids increase the chance for bleeding at any time during pregnancy. Usually, the amount of bleeding is minor and it is merely an inconvenience. However, if severe bleeding occurs, anemia and low blood count may result, potentially jeopardizing the health of the mother and fetus if it is not treated. Women with fibroids who experience bleeding during pregnancy should be followed closely by their doctor to ward off complications from blood loss.
Need for Cesarean Delivery
Women with fibroids have a six-fold greater chance for needing a cesarean section, according to WomensHealth.gov. Babies who develop alongside a fibroid are more likely to be in the breech, or feet- or bottom-down position. These days, most doctors refuse to deliver breech babies vaginally due to risks to the babies' health and insist on performing a cesarean section. Also, in rare cases, a fibroid could obstruct the passage of the baby out of the uterus, necessitating a surgical delivery. Although the vast majority of cesarean sections result in healthy babies, a cesarean constitutes major abdominal surgery that carries risks for both the mother and baby.
