Fibroids and Pregnancy
Fibroid tumors-also known as uterine myomas or leiomyomas-are extremely common in reproductive age women. A fibroid tumor is a benign mass of compacted muscle tissue that grows on or in the uterine wall. It’s estimated that approximately 30-50% of women between 25 and 45 years old have at least one fibroid tumor and they tend to be more common in the African American population than in other ethnic groups. The actual incidence, however, among pregnant women is probably about 10%. These tumors can be as small as a pea and occasionally can grow to the size of a grapefruit.
Fibroids usually develop prior to pregnancy and most women do not even know they have them unless they produce symptoms. The most common complaints are abdominal pain, heavy menstrual bleeding, pelvic pressure, urinary frequency and, occasionally, infertility and recurrent miscarriage. Fibroids can occasionally be diagnosed by physical exam but are often found incidentally at the time of an obstetrical ultrasound.
The diagnosis of a uterine fibroid during pregnancy can create a lot of anxiety. The reality, however, is that the vast majority of women with fibroids have uneventful pregnancies and deliveries. It was once thought that pregnancy induced rapid growth of most fibroids but studies have shown that almost 70% of fibroids do not grow in size and a small percentage actually shrink. Of those that grow during pregnancy, most recede after delivery.
Rarely, however, fibroids can complicate pregnancy. The most likely complication is abdominal pain related to rapid growth and degeneration of a fibroid. This may require treatment with pain medication and bedrest but is rarely dangerous to the pregnancy. There is also slightly increased risk of preterm labor, premature separation of the placenta (placental abruption), breech presentation and cesarean section.
Once the diagnosis is made, your obstetrician will work with you to decide on the best course of treatment and monitoring. Very likely she or he will monitor your pregnancy with periodic ultrasound examinations to monitor the growth of the baby. Your doctor may also decide to see you more frequently than normal and will ask you to call if you develop contractions or bleeding. By working closely with your obstetrician you can expect a normal pregnancy and a great outcome.
Eric G. Heegaard M.D. FACOG