Relationships of vaginal Lactobacillus species, cervical Chlamydia trachomatis, and bacterial vaginosis to preterm birth.

The frequency of genital infection was compared among women in premature labor who delivered preterm (before 37 weeks), women in preterm labor who delivered at term, and control women who delivered at term. Both groups of women in premature labor were younger and had more previous preterm births than did control women. Women in premature labor who delivered preterm were more likely to experience rupture of membranes, intrapartum fever, and postpartum fever than were control women. The presence of bacterial vaginosis (odds ratio 2.3) and Chlamydia trachomatis (odds ratio 3.9) was positively associated, and Lactobacillus sp (odds ratio 0.2) was negatively associated, with birth before 37 weeks, using multivariable analysis to control for confounding variables.