News Release

PHILADELPHIA – Depending on the specific type, bacteria in a woman’s vagina and cervix may increase the risk of premature birth or protect against it, according to new research from the Perelman School of Medicine at the University of Pennsylvania. Results of the study provide groundbreaking information that the authors suggest could help physicians learn how to prevent preterm birth, either by eliminating the “bad” bacteria, or increasing the “protective” bacteria. The study was presented this week at the Society for Maternal-Fetal Medicine’s annual meeting in Las Vegas, and received the March of Dimes Award for Best Abstract on Prematurity.

Premature birth (before 37 weeks of pregnancy) is the #1 killer of babies in the United States and the leading cause of death in children under age 5 around the world. Babies who survive an early birth often face serious and lifelong health problems, including breathing problems, jaundice, vision loss, cerebral palsy and intellectual delays. In addition to the human toll, preterm birth accounts for more than $26 billion annually in avoidable medical and societal costs, according to the National Academy of Medicine.

“For the first time in 8 years, the number of pre-term babies in the United States actually increased in 2016, and unfortunately, there are underlying causes that doctors still don't understand,” said lead author Michal Elovitz, MD, a professor Obstetrics & Gynecology at the Perelman School of Medicine at the University of Pennsylvania, director of the Maternal and Child Health Research Center at Penn, and a co-investigator for the March of Dimes’ Prematurity Research Center at the University of Pennsylvania. “Decoding the causes of prematurity has been a riddle that’s stumped researchers and clinicians for years, but our new study is finally shedding some light on a path toward offering treatment to women we can identify as being at-risk.”

In the study, researchers examined vaginal swabs from a sample of 2,000 pregnant women, taken at three distinct points in pregnancy, to determine the microbial colonies that were present. Analysis showed that among the many specific types of bacteria, some – such as certain bifidobacterium and lactobacillus species – actually lowered the risk of spontaneous preterm birth, while others – specifically several anaerobic bacteria – significantly increased the risk.

Elovitz says the new findings are the result of a multidisciplinary team of experts from immunology and microbiology, who came together and took a new approach to the issue, examining the cervix and vagina instead of limiting the scope of their study to the uterus, as conventional wisdom would suggest. The authors say more research is needed to confirm the findings, but if proven, it could mean treatments targeting “bad” cervical bacteria, or replenishing the “good” bacteria could be used to prevent premature birth in the immediate future.

Funding for the study was provided by the National Institutes of Health, and the National Institute of Nursing Research (R01NR014784).


Penn Medicine is one of the world’s leading academic medical centers, dedicated to the related missions of medical education, biomedical research, and excellence in patient care. Penn Medicine consists of the Raymond and Ruth Perelman School of Medicine at the University of Pennsylvania (founded in 1765 as the nation’s first medical school) and the University of Pennsylvania Health System, which together form a $8.6 billion enterprise.

The Perelman School of Medicine has been ranked among the top medical schools in the United States for more than 20 years, according to U.S. News & World Report's survey of research-oriented medical schools. The School is consistently among the nation's top recipients of funding from the National Institutes of Health, with $494 million awarded in the 2019 fiscal year.

The University of Pennsylvania Health System’s patient care facilities include: the Hospital of the University of Pennsylvania and Penn Presbyterian Medical Center—which are recognized as one of the nation’s top “Honor Roll” hospitals by U.S. News & World Report—Chester County Hospital; Lancaster General Health; Penn Medicine Princeton Health; and Pennsylvania Hospital, the nation’s first hospital, founded in 1751. Additional facilities and enterprises include Good Shepherd Penn Partners, Penn Medicine at Home, Lancaster Behavioral Health Hospital, and Princeton House Behavioral Health, among others.

Penn Medicine is powered by a talented and dedicated workforce of more than 43,900 people. The organization also has alliances with top community health systems across both Southeastern Pennsylvania and Southern New Jersey, creating more options for patients no matter where they live.

Penn Medicine is committed to improving lives and health through a variety of community-based programs and activities. In fiscal year 2019, Penn Medicine provided more than $583 million to benefit our community.

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