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Wednesday, May 29, 2019

NIH-funded study links microbiome composition to preterm birth risk among African-American women


A research project funded by the National Institutes of Health has identified differences in the vaginal bacteria that may raise the risk of preterm birth among pregnant African-American women. The findings could be a first step toward the development of a screen for the early identification of preterm birth risk in this population. The study was conducted by Jennifer Fettweis, Ph.D., of Virginia Commonwealth University in Richmond and colleagues. It appears in Nature Medicine.

The researchers analyzed a subset of more than 1,500 women participating in the NIH Common Fund’s Human Microbiome Project. They obtained samples of vaginal bacteria from 45 pregnant women who ultimately delivered preterm and compared them to similar samples from 90 pregnant women who delivered at term. Nearly 80% of the women in this subset, both those who delivered preterm and at term, were African-American, and the remainder were white, Hispanic, and American Indian/Alaska native.

The women who delivered preterm had a much more diverse microbiome in early pregnancy, compared to their peers. The preterm group had lower levels of the bacterium Lactobacillus crispatus, higher levels of BVAB1, a bacterium associated with a condition called bacterial vaginosis, and 12 other bacterial groups. The researchers linked this combination of bacterial species to the presence of immune system factors that promote inflammation. Previous studies have found higher levels of inflammation-promoting factors in women who deliver preterm. The authors note that larger studies are necessary to confirm their findings.

Funding for the study was provided by NIH’s Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD) the NIH Common Fund. Additional support was provided by the National Institute of Allergy and Infectious Diseases and the National Institute of General Medical Sciences.

Andrew Bremer, M.D., Ph.D., Acting Chief of the NICHD Pregnancy and Perinatology Branch, is available for comment.


Fettweis, JM, et al. The vaginal microbiome and preterm birth. Nature Medicine. 2019.

About the Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD): NICHD conducts and supports research in the United States and throughout the world on fetal, infant and child development; maternal, child and family health; reproductive biology and population issues; and medical rehabilitation. For more information, visit NICHD’s website.

About the National Institutes of Health (NIH): NIH, the nation's medical research agency, includes 27 Institutes and Centers and is a component of the U.S. Department of Health and Human Services. NIH is the primary federal agency conducting and supporting basic, clinical, and translational medical research, and is investigating the causes, treatments, and cures for both common and rare diseases. For more information about NIH and its programs, visit

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