The preterm prediction study: significance of vaginal infections. National Institute of Child Health and Human Development Maternal-Fetal Medicine Units Network.

OBJECTIVE

Our purpose was to evaluate the association of bacterial vaginosis, trichomonas vaginitis, and monilial vaginitis with spontaneous preterm birth at < 35 weeks 0 days.

STUDY

DESIGN

A total of 2929 women at 10 centers were studied at 24 and 28 weeks' gestation by Gram stain of vaginal smear, wet mount, and 10% potassium hydroxide preparations to detect vaginal infections.

RESULTS

The rates of detected infection at 24 and 28 weeks, respectively, were bacterial vaginosis 23.4% and 19.4%, trichomonas 3.3% and 2.7%, and monilia 21.1% and 19.5%. The occurrence of bacterial vaginosis at 28 weeks was associated with an increased risk of spontaneous preterm birth, odds ratio 1.84 (95% confidence interval 1.15 to 2.95, p < 0.01). Detection of Trichomonas vaginalis (by wet mount) or monilia (by potassium hydroxide preparation) had no significant associations with preterm birth.

CONCLUSION

The presence of bacterial vaginosis at 28 weeks' gestation is associated with an increased risk of spontaneous preterm birth.