Could something as simple as swishing your teeth with mouthwash be enough for pregnant moms to stave off a premature birth? A new study is offering an intriguing answer to that question.

The study, presented at the Society for Maternal-Fetal Medicine's annual meeting, suggests that mothers at high risk for an early birth can cut the risk by about two-thirds simply by using of an alcohol-free antibacterial mouthwash.

Each year, about 13 million babies around the world are born prematurely, leading to death in some and breathing an developmental difficulties in others.

A number of factors can increase the risk of preterm birth, such as a mother's low weight, smoking and drug abuse, but oral infections can also raise the risk.

So for this study, Dr. Marjorie Jeffcoat, a professor of periodontics at the University of Pennsylvania, led a team who recruited about 200 women in the early stages of pregnancy who also had periodontal disease, a gum disease that can lead to the gums and the bone around the teeth receding.

None of the women received any formal dental care during their pregnancy, but 49 were given an antimicrobial, alcohol-free mouth-rinse containing cetyl pyridinium chloride, or CPC. They were told to use the mouthwash twice a day. The rest of the mothers followed their usual routines.

The researchers found that 21.9 per cent of the women in the study group who didn't use the mouthwash gave birth to premature babies. But among those who did use the mouthwash, only 6.1 per cent had preemies.

As well, the babies from the mouthwash-using group were born later and had significantly higher birth weights.

Even the researchers were stunned with their results. Even after they adjusted their findings for smoking status of the women and their age, they still found a two-third reduction in premature birth.

"These results were so dramatic," Jeffcoat told CTV News. "There is a public health responsibility, in fact, to know what we found, to repeat it, to find out who should get it."

Jeffcoat explains that the hormones that surge in pregnancy also cause the gums to swell and become easily irritated. Too much of that inflammation may be what triggers early labour in some women.

"It all the same chemicals that are involved in giving birth and it is also what we want to avoid having in the mother's system," she said.

Dr. Anthony M. Iacopino of the Canadian Dental Association, who was not involved with the research, notes that other research has found that a mother's mouth bacteria can cause inflammation in the fetus and in the placenta, leading to premature birth.

He says the findings need further research to be confirmed, but are an important reminder to pregnant women that they need to see their dentist throughout their pregnancy – even though few actually do.

"We've always had patients who were a little bit leery about going to dentist when they are pregnant, although it is completely safe to have care provided during pregnancy," he says.

He says the study results should be for interest to those women who feel they can't afford dental care and are looking for things to do for their oral health at home.

"Using a mouth rinse is very cost effective and it is easy to do, anyone can do it. And if it is going to be effective, it is going to be a huge benefit for public health interventions," he said.

The study was partially funded by Procter and Gamble, which makes an antibacterial mouthwash. But some researchers wonder whether other products might work just as well.

"I would be interested to see the results from a variety of mouthwashes and see if they all have the same effect," said Dr. Anastaisa Cholakis of the University of Manitoba Faculty of Dentistry.

The researchers are now planning larger studies.

With a report from CTV medical specialist Avis Favaro and producer Elizabeth St. Philip