A growing body of medical research confirms the value of bringing a pregnancy to full term before delivery; babies born between the 39th and 40th week are generally healthier than those born sooner. Some medical complications come with the increased risk of preterm birth, but predicting when a woman will deliver has been an imprecise science so far. If the risk of early delivery could be pinpointed, measures could be taken to protect and prolong a pregnancy; researchers in Philadelphia report they may have found a way to do that as early as the second trimester.

Michal Elovitz, MD, is director of the Perelman School of Medicine at the University of Pennsylvania’s Maternal and Child Health Research Program. She and her team of researchers found indicators of preterm delivery in bacteria swabs taken from the vaginas of women at two stages of pregnancy. Those with a prevalence of a particular type of bacteria gave birth prematurely more often than those with less of it.

Swabs of cervicovaginal (CV) microbiota were taken at two points during each pregnancy:

  • Between weeks 20 and 24 (late second trimester)
  • Between weeks 24 and 28 (early third trimester)

The swab specimens were subjected to DNA testing to identify the types of microbial communities present in each woman. These community state types (CSTs) were categorized as:

  • CST I — Mostly Lactobacillus crispatus, which is usually a beneficial bacteria
  • CST III — Mostly Lactobacillus iners
  • CST IV — Anaerobic bacteria that contribute to bacterial vaginosis

Once each woman gave birth, the circumstances of delivery (early or full term) were matched with her CV biospecimens and compared with the birth outcomes of the entire group. The women who had low levels of CST I and CST IV bacterial types were more prone to deliver early.

According to Elovitz, hers is the first study “to report such key differences in the CV microbial communities weeks prior to preterm birth.” She foresees “new and exciting therapeutic strategies” to come as a result of her work but further study is needed to confirm her findings.

The desired further research is already underway. A large prospective cohort study is being done to strengthen the Elovitz findings. A prospective cohort study follows a clearly defined group of individuals (in this case, pregnant women) over a specific period of time. The study is being funded by the National Institute of Nursing Research.

Source: “Microbiota in late second and early third trimester differs in women who go on to have preterm birth.” ScienceDaily. ScienceDaily, LLC. Feb 3, 2014. Web. Feb 15, 2014.