Vanderbilt-led Study Disputes Link Between Uterine Fibroids and Miscarriage Risk

From the Summer 2017 edition of Vanderbilt Medicine Magazine

Study: Women with fibroids not at higher risk of miscarriage. Photo by istockphoto.com.

A 10-year study, led by Vanderbilt University Medical Center professor of Obstetrics and Gynecology Katherine Hartmann, M.D., Ph.D., disrupts conventional wisdom that uterine fibroids cause miscarriages.

The results of study appeared June 7 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,” Hartmann said.

Fibroids are common benign uterine masses that can distort the external and internal contour of the uterus. Changes in uterine architecture and other local effects of fibroids have been implicated in prior research as a risk factor for miscarriage.

“This is great news for women. Our results challenge the existing paradigm and have potential to reduce unnecessary surgical intervention,” said Hartmann, Lucius E. Burch Professor of Reproductive Physiology and Family Planning.

The study, “Prospective Cohort Study of Uterine Fibroids and Miscarriage Risk,” included women from eight urban and suburban communities in three states to achieve a racially diverse cohort of women planning pregnancies or in the early weeks of pregnancy. Each woman in the Right from the Start study had a standardized ultrasound for fibroids to determine presence, number, size and location in the uterus.

Of the more than 5,500 women enrolled, ultrasound detected uterine fibroids in 11 percent, while 89 percent of the study participants did not have fibroids. The chance for miscarriage in both groups was 11 percent.

Investigators from Vanderbilt, University of North Carolina-Chapel Hill and the National Institutes of Health (NIH) National Institute of Environmental Health Sciences, accrued the largest prospective cohort to date to investigate the association of fibroids with miscarriage, said Hartmann, the study’s principal investigator.