Source 23

The commonest systemic condition that leads to periodontal disease is the variation in the hormonal levels. The increased levels of the hormones during pregnancy affect many organs in the body and periodontium is no exception. Gingivitis is a common feature of pregnancy. It is caused by bacterial plaque just as it is in non-pregnant individuals.
The estrogen and progesterone receptors have been recog- nized in the gingiva, these receptors exacerbate the gingival response to plaque. The imbalance or increased levels of these hormones modifies the bacterial composition of plaque resulting in the growth of gram-negative anaerobic microbiota which modifies the resultant clinical picture in pregnancy.
Pre-term/low birth weight (PLBW) infants represent a major medical, social and economic problem accounting for a large proportion of maternal and especially neonatal mor- tality and morbidity. Offenbacher et al showed the relation between the periodontal disease and preterm infants who are born before 37 weeks of gestation and low birth weight infants, birth weight < 2500 g.
The various risk factors for preterm delivery and low birth weight infants are low maternal age, first delivery, history of PLBW, abortion, habits like tobacco, coffee, drug abuse, edu- cation, and gender of fetus. Offenbacher et al hypothesized that gram-negative anaerobic pathogens from periodontium and associated endotoxins and maternal inflammatory mediators could have a possible adverse effect on the developing fetus.
Experiments carried out by Collins et al in the pregnant hamster model showed that periodontitis can affect fetal growth.2 Later human case-control studies performed by Dasanayke, Davenport et al, Offenbacher et al, demonstrated that women who have low birth weight infants as a consequence of premature rupture of membranes tend to have more severe periodontal disease than mother with normal weight infants.
Since birth weight is easier to ascertain than gestational age, especially in countries like India, where no ultrasound scan is carried out in early pregnancy, many have advocated the use of birth weight for the definition of preterm birth rather than gestational age.
The following study was undertaken to study the risk fac- tors for preterm delivery and low birth weight infants and the prevalence of periodontal disease among mothers of the study population.