Risk of Pre-term Birth Associated with Gum Disease?

The womb is even farther from the gum line than the heart, yet several studies have linked dental infections with spontaneous pre-term birth. This research began in the mid-1970s.

Marjorie Jeffcoat of the University of Alabama, Birmingham, reasoned that -- since other infections have been shown to cause premature births of low-birth-weight babies -- dental infections may have a similar impact.

If they could, researchers thought, it would help explain the 25%-50% of premature births that are unexplained. It might also explain why so many more black women, who are often unable to gain access to dental care, have premature, low-birth-weight infants than white women.

She and her colleagues studied 120 women from rural parts of the state and found that women with dental infections were three times more likely to have premature, low-birth-weight infants.

Steven Offenbacher of the University of North Carolina and his colleagues did a similar study on 124 women but found a sevenfold increase in risk. He and his team also gave hamsters low-grade skin infections, using an oral bacterium found in humans. Sure enough, the researchers reported in 1994 that infected hamsters had more pre-term and smaller fetuses than uninfected ones.

These studies, though interesting, were inconclusive.

More study under way

Now Jeffcoat and her colleagues in Alabama -- including obstetricians -- plan to study 4,000 women, 1,000 of whom have already been recruited. These women will be examined while they're pregnant, and the outcome of each pregnancy will be recorded. About 400 of those with gum disease will be treated. Some will have their teeth cleaned, others will have a full-scale periodontal treatment with antibiotics. ``We want to see if we can cut down their risk,'' Jeffcoat says.

That remains an open question in each of the research fields described, says Mangan of NIDR. Researchers are still trying to determine whether there's a problem, and if so how extensive it is. ``We're new at this,'' he says.