Uterine Fibroids and Pregnancy

Uterine fibroids are non-cancerous tumors that grow within the muscle tissue of the uterus. Approximately 20-50% of women affected by uterine fibroids are of childbearing age(1).
While patients with uterine fibroids may get pregnant and have natural deliveries, several studies have suggested that the size and location of the fibroid within the uterus may weaken fertility and cause pregnancy complications that may arise due to fibroid growth in the uterus (2, 3). 

Uterine fibroids may lead to a number of complications during pregnancy. These include:

• Bleeding during the first trimester (2)
• Placenta Displacement (2) - Increased estrogen may cause accelerated fibroid growth. If the fibroid  grows during pregnancy then there is a risk that it will move or tear the placenta.
• Caesarian Section (4) - Multiple fibroids located in the lower part of the uterus may block the birth canal. In this case a caesarian birth is necessary.
• Premature Labor (4) - A pregnant woman with uterine fibroids is at greater risk of premature delivery, depending on the location and shape of the fibroid(s).
• Miscarriages (2) - Fibroids may act as an obstruction in the uterus which prevents the embryo from developing and ultimately causes a miscarriage.

Generally uterine fibroids are not removed during pregnancy due to the increased risk of hemorrhage. It is possible that between weeks 12-22 the blood supply to the fibroid may stop causing it to turn red and die, this is called “Red Degeneration” (4). When this occurs it causes intense abdominal pains and contractions which may lead to premature labor or even miscarriage.
In spite of the various complications, many patients with uterine fibroids who do get pregnant, have normal pregnancy and successful deliveries (4).

What are common symptoms of uterine fibroids?

What uterine fibroid treatments are available?

References:
1. Walker CL, Stewart EA. Uterine fibroids: the elephant in the room, Science, 2005, 308:1589-92.
2. Coronado GD, Marshall LM, Schwartz SM. Complications in pregnancy, labor and delivery with uterine leiomyomas: a population based study, Obstet Gynecol., 2000, 95:764-9.
3. Yoon SW, Kim KH, Kim SH, Ha DH, Lee C, Lee SY, Jung SG, Kim SJ. Pregnancy and natural delivery following magnetic resonance imaging-guided focused ultrasound surgery of uterine myomas, Yonsei Med J, 2010, 51(3):451-453.
4. Hasan F, Arumugam K, Sivanesaratnam V. Uterine Leiomyomata in pregnancy, Int. J Gynecol Obstet, 1990, 34:45-48.