Background: The aim is to examine bacterial vaginosis (BV) in women with preterm and term labor, explore the link between bacterial vaginosis and preterm labor (PTL), and analyze complications for both mother and baby related to bacterial vaginosis.

Design: Hospital based cross sectional study.

Materials and Method: We had conducted an observational study at Basaveshwara Medical College and Hospital, involving 100 pregnant patients with preterm and term labor (50 patients in each group). Eligible patients attending the Obstetrics and Gynecology Outpatient Department (OBG OPD) and inpatient department will be included. Bacterial vaginosis will be determined using Amsel's criteria, which include evaluating discharge characteristics, vaginal pH, amine odor with KOH test, and presence of clue cells under microscopic examination. Additionally, vaginal swabs will undergo Gram staining.

Results: The percentage of patients meeting Amsel's criteria for diagnosing bacterial vaginosis was significantly higher in the preterm labor group compared to the term labor group, with a statistically significant difference. According to Amsel's criteria, the prevalence of bacterial vaginosis was 30% in the preterm labor group and 2% in the term labor group.

Conclusion: Bacterial vaginosis is a significant risk factor for preterm labor. Hence, conducting tests for bacterial vaginosis and promptly treating it can help reduce the risk of preterm labor.