While it is common knowledge that smoking, alcohol use, and drug use contribute to pre-term labor, low birth weight infants, periodontal disease is just another risk factor to pregnancy problems.
Some studies have suggested that pregnant women with periodontal infection are more likely to have a low birth weight premature baby. To confirm how this oral disease affects pregnancy outcomes still requires more research.
Any infection no matter the origin is cause for concern for a pregnant woman because they poses a risk to the health of the baby. We recommend that women considering pregnancy have a periodontal evaluation.
Resource link: https://secure.perio.org/consumer/prematurity-studies.htm