Uterine Fibroids and Miscarriage

These Lumps of Tissue Can Occasionally Wreak Havoc

Uterine Fibroids
Fibroids in the uterus can sometimes cause recurrent miscarriages.. Image © A.D.A.M.

What Are Fibroids?:

Fibroids are lumps of tissue—benign tumors—that grow in the wall of the uterus. Fibroids are not uncommon; estimates suggest that anywhere between 20% and 50% of women have some type of fibroid. Fibroids usually develop during adulthood and are not present from birth.

Symptoms:

In many women, fibroids cause no problems. Some women, however, may experience pelvic pain, unusually heavy menstrual periods, or fertility problems.

In some women, fibroids can cause recurrent miscarriages.

Why Fibroids Are Related to Miscarriages:

According to a 2000 study, fibroids are the exclusive culprits in 5% of women who are infertile or miscarry. Doctors believe that the reason why fibroids cause problems for some women and not others has to do with the type and size of the fibroid and its location in the uterus.

For instance, if the fibroid is closer to the middle of the uterus, where a fertilized egg is more likely to implant, then the fibroid is more likely to cause a miscarriage. Fibroids that stick out into the uterine cavity and change its shape (submucous fibroids) and ones that are within the uterine cavity (intracavity fibroids) are more likely to cause miscarriages than ones that are within the uterine wall (intramural fibroids) or bulge outside the uterine wall (subserosal fibroids). A large fibroid tends to be more problematic than a small one.

The bigger a fibroid is, the more blood vessels it contains, and the more it can take blood flow away from the uterus and a developing fetus. 

How Doctors Diagnose Fibroids:

Doctors can frequently diagnose fibroids by doing a pelvic exam. If the doctor wants more information about the fibroids, especially for a woman who is having miscarriages or fertility issues, the doctor may also order a hysterosalpingogram (HSG) or a sonohysterogram.

During an HSG, a 30-minute outpatient procedure, an iodine-based dye is placed through the cervix and x-rays are taken. A sonohysterogram involves injecting saline solution into the uterus and examining it with ultrasound.

Treatment Options:

Multiple treatments exist for fibroids, and women who have no negative symptoms associated with their fibroids may not even need treatment.

The most drastic treatment for fibroids is hysterectomy (removal of the entire uterus)—a treatment that would obviously not work for anyone who has a goal of getting pregnant again.

Medications that can shrink fibroids also exist, as do other surgical procedures that are less drastic than hysterectomy. One procedure called uterine artery embolization halts the blood supply to the fibroid and has shown increasing success, but the safety of pregnancy after the procedure is unknown.

A surgery called myomectomy is usually a top choice for a woman who is hoping to get pregnant again. In a myomectomy, the doctor surgically removes the fibroid, sometimes via a hysteroscope or a laparoscope.

The downside of myomectomy as a fibroid treatment is a significant chance of the fibroid recurring; 10% to 25% of women who choose myomectomy as a fibroid treatment will need a repeat myomectomy in the future because of new fibroids. In addition, women who have had a myomectomy may have an increased risk of uterine rupture during pregnancy and will need to be followed extra closely during prenatal care.

Sources:

Bajekal, N., and T.C. Li, "Fibroids, infertility, and pregnancy wastage." Human Reproduction Update 2000. Accessed 24 Feb 2008.

Hart, Roger, Yacoub Khalaf, Cheng-Toh Yeong, Paul Seed, Alison Taylor, and Peter Braude, "A prospective controlled study of the effect of intramural uterine fibroids on the outcome of assisted conception." Human Reproduction Nov 2001. Accessed 24 Feb 2008.

Stewart, Elizabeth A., "Patient information: Fibroids." UpToDate Patient Information. Sept. 2007. Accessed 24 Feb 2008.

http://www.fibroidsecondopinion.com/fibroids-and-pregnancy/

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