Vaginal infection and preterm labour

Objective— To study the vaginal flora of women in preterm labour (PTL) and determine whether the presence of specific vaginal microflora is significantly associated with onset of PTL. Design— A comprehensive prospective study of the vaginal microflora of women in early labour comparing women in PTL with term controls. Microbiological assessment included cultures for aerobic and anaerobic bacteria, yeasts, genital mycoplasmas and Trichomonas vaginalis. Multiple logistic regression analysis was used to adjust for confounding obstetric and demographic variables. Setting— The Queen Victoria Hospital, Adelaide. Patients— 428 Women in PTL compared to 568 women in labour at term. Main outcome measure— PTL and preterm prelabour rupture of membranes (PPROM) in relation to specific vaginal microflora. Results— After multiple logistic regression analysis, two distinct bacteriological groupings were associated with PTL <37 weeks gestation, namely, the bacterial vaginosis group of organisms, Gardnerella vaginalis and Bacteroides spp., and a group of enteropharyngeal organisms, E. coli, Klebsiella spp., Haemophilus spp. and S. aureus. G. vaginalis was found in 12% of women in PTL compared to 6% at term [regression odds ratio (ROR) 1.8, 95% confidence intervals (CI) 1.1–3.1] whereas Bacteroides spp. were detected in 45% of women in PTL compared with 35% at term (ROR 1.6, CI 1.2–2.1). The prevalence of G. vaginalis (17%) and Bacteroides spp. (50%) was even higher in women in PTL <34 weeks gestation. The enteropharyngeal group of organisms were more commonly present in women in PTL <37 weeks (E. coli 10% vs 6%, ROR 1.4, CI 0.8–2.4; Klebsiella spp. 3% vs <1%, ROR 5.4, CI 1.1–26.7; Haemophilus spp. 2% vs <1%, ROR 5.5, CI 1.1–28.6; aureus 6% vs 4%, ROR 1.8, CI 0.9–3.3) and were isolated even more frequently in women in PTL <34 weeks (E. coli 15%; Klebsiella spp. 4%; S. aureus 7%). Bacteroides spp., Klebsiella spp., and Haemophilus spp. were all found to be associated with PPROM. Conclusion— There are two distinct bacteriological groupings commonly found in women in PTL, especially in PTL <34 weeks gestation. These bacteriological groups are women with bacterial vaginosis in pregnancy and women who demonstrate enteropharyngeal bacteria in the vagina.