Longitudinal trajectory of bacterial vaginosis during pregnancy

This study was undertaken to characterize the course of bacterial vaginosis in pregnancy and to discern the bacterial morphotypes responsible for infection.

Vaginal secretions were obtained in each trimester of pregnancy and were evaluated for bacterial vaginosis by Gram stain, categorized as normal or any of the following: Lactobacillus deficient, Gardnerella, Bacteroides, or Mobiluncus positive and by Nugent score. Results were evaluated for trends of bacterial vaginosis and Gram stain over pregnancy.

One hundred forty-eight women were evaluated. Seventy-one women (48%) were bacterial vaginosis negative in all trimesters, compared with 14 (9.4%) who were positive throughout pregnancy. Among the 14 women who remained bacterial vaginosis positive, Gram stain findings were Gardnerella+Bacteroides+Lactobacillus, with approximately 50% harboring Mobiluncus. Few women become bacterial vaginosis positive as pregnancy progressed (6.1%). With each increasing week of pregnancy, the risk of becoming bacterial vaginosis positive decreased (0.93: 0.91-0.95; P < .001).

In this population, the majority of pregnant women trend toward bacterial vaginosis negative status. Few women are bacterial vaginosis positive across their pregnancy.