Throughout history, there has been the belief that diseases that affect the mouth, such as periodontal disease, can have an effect on the rest of the body. It is only very recently that scientists and clinicians have begun to provide an increasing body of scientific evidence suggesting that moderate untreated Periodontitis may affect an individual systemically, and may contribute to cardiovascular disease, diabetes, and preterm low birth weight. Birth weight is affected by multiple factors and is considered as an outcome of a complex multifactorial system. Periodontitis is a remote gram-negative infection that may play a role in low birth weight. Periodontopathic microorganisms and their products have a wide range of effects mediated through host cytokine production in target cells. Many combined animal studies and data supporting plausible biologic mechanisms suggest that periodontal infection has a negative impact on pregnancy outcome in some women.