Abstract: 【ABSTRACT】Objective: To investigate the effect of pregnant women with periodontitis on premature birth and low birth weight. Methods: Randomly selected Xingtai City,the Third Hospital of stomatology in 2008 July to 2013 February treatment of pregnant and lying in women as the object of study,including pregnancy found suffering from periodontitis and timely treatment (group 1),found during pregnancy periodontitis and active treatment (Group Ⅰ),pregnancy with periodontitis without treatment or treatment is not complete (Group Ⅲ),pregnancy and pre pregnancy were not suffering from periodontitis of healthy pregnant women (Group IV) four groups,200,to carry out the questionnaire and oral examination,compared with four groups of maternal neonatal outcomes. Results: There was no significant difference in the rate of preterm birth and low birth weight infants (P＞0.05),and the rate of preterm birth and low birth rate in group B was significantly lower than that in group P＜0.05. Conclusion: Pregnancy with periodontitis without active treatment or treatment is not proper,prematurity and low birth weight infants is extremely easy to occur,therefore,we should strengthen during pregnancy oral health instruction,the inclusion of oral health care in promoting the eugenics,minimize adverse pregnancy.