Uterine fibroids are common benign tumors of the myometrium. Up to 70% of white women and 90% of African American women will develop fibroids by age 50 years. About one quarter of reproductive-age women will experience symptoms, which are either associated with menstruation (menometrorrhagia, dysmenorrhea) or are related to the size of the fibroid (pressure, fullness). In addition to genetic factors, steroid hormones and growth factors have been implicated in the growth of fibroids.
Fibroids may or may not interfere with fertility. In general, it is believed that myomas that distort the uterine cavity are associated with infertility and pregnancy loss. Subserosal fibroids that grow outside the uterus do not seem to have a negative reproductive effect. The role of intramural fibroids is more controversial, however.
This large, matched observational study evaluated the impact of non–cavity-distorting intramural myomas on the outcome of in vitro fertilization (IVF).
The study included women who were diagnosed with intramural fibroids that did not distort the cavity and who were scheduled to undergo IVF. The intactness of the uterine cavity was confirmed by hysterosalpingography or hysteroscopy. Each case was matched with two controls with no fibroids seen on ultrasound. Cases and controls were matched for age, starting dose of follicle-stimulating hormone, embryo transfer on day 3 versus day 5, and the number of embryos transferred.
Here’s what the researchers reported:
- Overall, the clinical pregnancy rate (32.5% vs 42.6%; odds ratio [OR], 0.62; 95% confidence interval [CI], 0.41-0.94) and the live birth rate (26.9% vs 37.4%; OR, 0.58; 95% CI, 0.48-0.78) were lower in women with fibroids versus those without fibroids, respectively.
- Pregnancy and live birth rates were similar in women with a single fibroid versus no fibroid, but were significantly lower in women with two or more fibroids than in women without fibroids.
- Fibroids smaller than 3 cm were not associated with a significant negative impact on clinical outcome, but with larger fibroids, the pregnancy and live birth rates were lower than in women with no leiomyomas.
Read more about the fertility research here: