Incidence of bacterial vaginosis and its relation to preterm delivery

Bacterial vaginosis is characterized by the presence of large amounts of anaerobic bac­teria, Gardnerella vaginalis and Mycoplasma hominis in the vagina, where they replace the nor­mally present lactobacilli. The condition is impli­cated as a possible cause of preterm delivery. In our study, bacterial vaginosis was diagnosed clin­ically and microbiologically. The incidence of bac­terial vaginosos in 72 pregnant women attending the Clinic for Pathologic Pregnancy (5.5%) was lower than that in 100 women examined prior to artifical abortion at the Day Clinic (14%) and in 23 women evaluated at the Clinic for Sexually Transmitted Diseases (23.0%). The difference in incidence between the groups was not statistically significant. Factors found to be significantly asso­ciated with bacterial vaginosis included: smoking 15 or more cigarettes per day (odds ratio 7.15; 95% contidence interval 1.9–26.0) and age < 17 years at the first sexual intercourse (odds ratio 3.64; 95% contidence interval 2.2–7.1). The inci­dence of bacterial vaginosis is higher among non-pregnant women than among pregnant ones (odds ratio 3.22; 95% contidence interval 1.5–6.8), and in the first and second trimester of pregnan­cy than in the third (odds ratio 2.22; 95% conti­dence interval 0.9–5.2). Sexual habits and cigarette smoking seem to predispose women to bacteri­al vaginosis. The condition may resolve sponta­neously during pregnancy. The pH determination and amine odour of the vaginal discharge can be used as a reliable screening test, while Gram-stain reading of the vaginal smear is employed to cor­roborate the diagnosis. Because of the small size of the series studied, it was not possible to prove the relationship between bacterial vaginosis and preterm delivery.