A new study sheds light on what may be causing premature birth. Findings of the research published in the January 8 online issue of the journal Plos One suggest that certain bacteria may cause the thinning of the membranes surrounding the baby which cause them to tear. The condition is called preterm premature rupture of the membranes (PPROM) and nearly one-third of early deliveries are associated with it.

Researchers at the Duke University School of Medicine analyzed samples of amniotic sacs, the fetal membranes, from 48 women after they give birth, including those with PPROM, those who had an early birth for other reasons, and those with babies born at full term, and found that the more bacteria present in the membranes, the thinner the membranes are especially in women with PPROM.

A high percentage of premature deliveries are associated with PPROM and researchers say it is important to learn more why this happens. "Complications of preterm births can have long-term health effects for both mothers and children," study author Amy Murtha, associate professor of obstetrics and gynecology at Duke University School of Medicine, said in a news release.

The researchers said that further study is needed to determine whether the presence of high levels of bacteria is a cause or the result of the fetal membrane weakening. "Our research is several steps away from this, but it gives us opportunities to explore potential targeted therapeutic interventions, which we lack in obstetrics," Murtha said

The researchers are also investigating whether certain types of bacteria may increase the risks of PPROM. "For instance, if we think that certain bacteria are associated with premature rupturing of the membranes, we can screen for this bacteria early in pregnancy," Murtha said. "We then might be able to treat affected women with antibiotics and reduce their risk for PPROM."

Meanwhile, Patrick O'Brien from the Royal College of Obstetricians and Gynaecologists in UK said that it had been known for a while that bacterial infection causes PPROM in some women. "We've long suspected and known that bacteria are involved in a large proportion of these women. What we really need to know now is to understand the detailed mechanism of how bacteria cause the waters to break," he said.