Bacteria could cause premature births, according to a new study. Preterm births occur when a pregnant woman’s water breaks early. Researchers, including Amy P. Murtha from Duke University School of Medicine, wanted to find out why water sacs break early in some women. They hoped to understand the mechanisms behind early membrane rupture.

The water sac, formally known as the fetal membrane, actually contains two transparent membranes that hold the fetus. The inner membrane contains the fetus and amniotic fluid, which keeps the baby warm and provides lubrication for growing body parts. The outer membrane, known as the chorion, is part of the placenta; this tough membrane encloses the fetus and contains fluid that suspends the baby. These membranes rupture when a pregnant woman “breaks water.”

Premature birthPreterm births occur when the water sac surrounding the baby breaks before the baby reaches full term. Almost a third of all early deliveries are the result of a condition known as premature preterm rupture of membranes, or PPROM. Preterm births negatively affect the health of both mother and baby; complications can have long-term effects.

In this new study, researchers examined samples of the chorion membranes of 48 women who had pre-term and full-term deliveries. The scientists measured the thickness of the chorion membrane and tested for the presence of bacteria in many locations on the membrane.

The scientists determined that ruptures occurred at the thinnest location of the membrane in all the test subjects. However, patients who tested positive for bacteria showed membrane thinning at locations other than the rupture site. They found bacteria at the rupture site and across the membrane. Additionally, the scientists discovered that the thinner the membrane, the more bacteria were present.

The researchers found bacteria near areas where the chorion walls of the water sac are thinner. They also discovered that women with infections of the chorion membrane had high rates of cell death in these layers.

Published in the online version of the medical journal PLOS ONE, Murtha says her research only establishes a link between bacteria and preterm birth – it does not determine whether one causes another. She encourages further research.

Source: Paddock, Catharine. "Bacteria 'could be a cause of preterm births'." Medical News Today. MediLexicon, Intl., 10 Jan. 2014. Web. 20 Jan. 2014.