Do vaginal lactobacilli prevent preterm labour?
Objective. To determine the prevalence of Lactobacillus spp. in vaginal flora during pregnancy and to assess the protective effects of lactobacilli against preterm labour. Design. Cross-sectional analysis of Lactobacillus spp. in the vaginal flora of the pregnant coloured population of the Western Cape. Participants. A total of 480 consecutive pregnant women, aged 13-48 years, seen at their first visit to the Tygerberg Hospital antenatal clinic. Main outcome measures. Preterm labour, i.e. before 34 and 37 weeks' gestation, premature rupture of membranes, intra-uterine growth retardation and perinatal deaths. Results. A total of 163 patients had negative cultures and 317 positive cultures for lactobacilli, aerobes or both. Delivery before 37 weeks occurred in 18% and 20% of the two groups, respectively. Lactobacillus only was cultured from 116 patients and Lactobacillus and/or other aerobes from 201 patients. Preterm labour occurred in 20% of the first group and in 19% of the second group. The perinatal outcome in patients from whom lactobacilli only were cultivated did not differ from patients from whom other aerobes and lactobacilli or other aerobes only were cultured. Conclusion. In patients at high risk for preterrn labour, the presence of lactobacilli in the vagina does not seem to play a protective role.