Uterine Fibroids and Miscarriage Link Disputed

National Institute of Environmental Health Sciences (NIEHS; Research Triangle Park, NC, USA), and other institutions conducted a prospective cohort study to determine the relationship of fibroids to pregnancy loss. The 5,512 study participants, who were recruited from eight metropolitan areas in three U.S. states between 2000 and 2012, underwent an intake interview, transvaginal ultrasonography, a computer-assisted telephone interview, and follow-up assessment of outcomes.

The results revealed 10.4% of the women had at least one fibroid, and 10.8% experienced miscarriage; 23% had experienced a prior miscarriage and 52% had prior births. While fibroids were associated with miscarriage in models without adjustments, factoring in key confounders indicated no increase in risk, and no characteristic of fibroids was associated with risk. The researchers concluded that prior evidence attributing miscarriage to fibroids is potentially biased, and that the findings imply that surgical removal of fibroids to reduce risk of miscarriage deserves careful scrutiny. The study was published on June 7, 2017, in the American Journal of Epidemiology.

“Women with fibroids had identical risk of miscarriage as women without fibroids, when taking into account other risks for pregnancy loss. We were stunned,” said lead author professor of obstetrics and gynecology Katherine Hartmann, MD, PhD. “This is great news for women. Our results challenge the existing paradigm and have potential to reduce unnecessary surgical intervention. The key message is that fibroids don't seem to be linked to miscarriage.”

A uterine fibroid (leiomyomata) is a benign tumor from smooth muscle tissue that originates from the smooth muscle layer (myometrium) of the uterus. Fibroids are often multiple and if the uterus contains too many to count, it is referred to as diffuse uterine leiomyomatosis. Fibroids are the most common benign tumors in females and typically found during the middle and later reproductive years. While most are asymptomatic, they can grow and cause heavy and painful menstruation, painful sexual intercourse, and urinary frequency and urgency.

Related Links:
Vanderbilt University Medical Center
U.S. National Institute of Environmental Health Sciences