To systematically review studies reporting the risk of spontaneous abortion among pregnant women of typical reproductive potential with and without uterine leiomyomas.
We searched PubMed, EMBASE, Web of Science, and ClinicalTrials.gov for publications from January 1970 to December 2016.
We excluded studies that did not use imaging to uniformly document leiomyoma status of all participants, did not have a comparison group without leiomyomas, or primarily included women seeking care for recurrent miscarriage, infertility care, or assisted reproductive technologies.
Two authors independently reviewed eligibility, extracted data, and assigned overall quality ratings based on predetermined criteria. Of 1,469 articles identified, nine were eligible. Five enrolled general obstetric populations and four included women undergoing amniocentesis. In five studies in general obstetric populations that included 21,829 pregnancies (1,394 women with leiomyomas and 20,435 without), only one adjusted for potential confounders. This meta-analysis revealed no increase in risk of spontaneous abortion among those with leiomyomas compared with those without (11.5% compared with 8.0%; risk ratio 1.16, 95% CI 0.80–1.52). When bias from confounding was estimated for nonadjusted studies, the aggregate calculated risk ratio was 0.83 (95% CI 0.68–0.98).
Leiomyoma presence was not associated with increased risk of spontaneous abortion in an analysis of more than 20,000 pregnant women. Failure of prior studies to adjust for confounders may have led to the common clinical belief that leiomyomas are a risk factor for spontaneous abortion.
Leiomyoma presence during pregnancy is not associated with increased risk of spontaneous abortion in general obstetric populations.
Vanderbilt Epidemiology Center, Institute of Medicine and Public Health, the Vanderbilt Genetics Institute, the Evidence-Based Practice Center, and the Department of Obstetrics and Gynecology, Vanderbilt University Medical Center, Nashville, Tennessee.
Corresponding author: Digna R. Velez Edwards, MS, PhD, 2525 West End Avenue, Suite 600, Nashville TN 37203; email: Digna.R.Velez.Edwards@vanderbilt.edu.
Supported by CTSA award number UL1TR000445 from the National Center for Advancing Translational Sciences and by the Public Health Service award (T32 GM07347) from the National Institute of General Medical Sciences for the Vanderbilt Medical-Scientist Training Program.
Financial Disclosure The authors did not report any potential conflicts of interest.
The authors thank Nila Sathe (Vanderbilt's Evidence-Based Practice Center) for assistance in designing the protocol and Rachel Lane Walden (Vanderbilt Biomedical Library Services) for refining the search criteria.
Each author has indicated that he or she has met the journal's requirements for authorship.