Background: 8-10% pregnancies end in preterm labour or threatened preterm labour which has maternal and foetal complications just due to infections such as bacterial vaginosis, which can be identified by simple tests like Amsel Criteria and treated at the earliest with appropriate antibiotics. Aim: The prevalence of bacterial vaginosis in preterm & threatened preterm labor based on amsel’s criteria and treatment of bacterial vaginosis in managing preterm & threatened preterm deliveries. Materials and Methods:  The study was carried out in department of obstetrics & gynaecology, Government Rajaji hospital, Madurai medical college,  Madurai. 200 women with symptoms of preterm & threatened preterm labour. Examination of vaginal discharge,vaginal pH, microscopy for clue cells and Whiff test, which are Amsel’s criteria,  were done. Chi-square test was used to find outthe association of variables and p value less than 0.05 was taken as statistically significant. Results: There was  significant association between bacterial vaginosis and preterm labour.There was significant association between bacterial vaginosis and delivery of low birthweight babies.There was strong evidence that treatment of bacterial vaginosis in preterm & threatened preterm reduces the  neonatal complications. Conclusion: The prevalence of bacterial vaginosis was 30% in preterm & threatened preterm deliveries. There was a significant association between bacterial vaginosis and preterm labour. There was also significant association of various factors like low socio economic status, low BMI and history of previous preterm deliveries to the study group. There was storng evidence that treatment of bacterial vaginosis in preterm & threatened preterm deliveries reduce the neonatal complications.

Keywords: Bacterial Vaginosis; Gardnerella Vaginalis; Amsel’s Criteria.