A new study suggests that scaling a woman's teeth may significantly reduce her chance of having a preterm birth. Interestingly, the researchers found no evidence that the addition of an antibiotic to scaling and root planing was of benefit in this study.
However, a far more powerful and important factor for prevention of premature births would be taking enough high-quality omega-3 fish oil as I described in an article earlier this year.
BBC News August 27, 2003