Mechanisms of risk in preterm low-birthweight infants.

The periodontal diseases share many common risk factors with preterm low birth weight. Examples are, age, socioeconomic status and smoking (Fig. 5). Studies to date have only shown an association between the two conditions, and this does not indicate a causal relationship. However, since the inflammatory mediators that occur in the periodontal diseases, also play an important part in the initiation of labor, there are plausible biological mechanisms that could link the two conditions. The challenge for the future is to characterize the nature of the factors that predispose a mother to give birth prematurely to infants less than 2500 g and to assign relative probabilities to each. Studies are taking place in many parts of the world to determine the probability of a preterm low-birth-weight outcome, the interdependence of the factors that contribute to a birth event and possible casual relationships between these factors. Further information about the details of the effects of maternal infection will come from intervention studies, animal studies and more detailed examination of the mechanisms.