How Intramural Uterine Fibroids May Affect IVF Outcomes

Peter Kovacs, MD, PhD


July 06, 2017

Fibroids That Do Not Distort the Uterine Cavity and IVF Success Rates: An Observational Study Using Extensive Matching Criteria

Christopoulos G, Vlismas A, Salim R, Islam R, Trew G, Lavery S
BJOG. 2017;124:615-621


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.[1] 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).[2] In addition to genetic factors, steroid hormones and growth factors have been implicated in the growth of fibroids.[3,4]

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.[5] 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.[6,7]

This large, matched observational study evaluated the impact of non–cavity-distorting intramural myomas on the outcome of in vitro fertilization (IVF).

Study Summary

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.

The analysis included 163 women with fibroids and 326 controls. There were no demographic or IVF parameter-related differences between the groups.

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.


Fibroids are common benign tumors of the uterus that could have a negative reproductive effect. This negative impact may be mediated through alterations in uterine or endometrial blood flow, may affect uterine contractility, or may modify endometrial function at the molecular level.[8] Furthermore, fibroids that distort the cavity may physically interfere with implantation or embryo growth. For this latter reason, the negative role of submucous fibroids seems straightforward.

The impact of intramural fibroids is more controversial, however. This study found that multiple (more than two) and larger (> 3 cm) intramural fibroids, even if they do not distort the cavity, lower IVF success rates. The question, is what to do with these fibroids?

When treatment is offered, surgical removal is considered as first-line therapy in infertile women. Surgery, however, results in scarring, perioperative morbidity or mortality, and a delay in the start of fertility treatment.[9] Furthermore, except for hysteroscopic removal of submucous fibroids, it has not been shown to increase pregnancy or live birth rates.[10,11] Radiologic and medical treatments could be considered as an alternative to surgery,[12,13] but none of these treatments has yet been studied in randomized controlled trials.

For now, we are left with the need to have a detailed discussion with our patients. They need to be informed that their chance of successfully conceiving is likely to be affected by larger and multiplex intramural fibroids. Patients also need to be informed about the lack of proper evidence for surgical, medical, or radiologic treatment to improve fertility. Such treatments can, however, still be offered upon proper counseling, especially to women with previous pregnancy loss or multiple fertility treatment failures.



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