Risk score for antenatal bacterial vaginosis: BV PIN points

Develop a clinical risk score to screen for antenatal bacterial vaginosis (BV), irrespective of symptoms.

Cohort study of 913 pregnant women with last menstrual periods between January 30, 1995 and February 22, 1997. BV was evaluated by Nugent-scored vaginal smears (scores of 7 to 10 considered positive) between 24 and 29 weeks' gestation. Forty-four potential risk factors were assessed.

17.8% of women had BV, of whom 22% were screened for BV by the usual care provider. Logistic regression-adjusted analyses found six predictors: vaginal pH>4.5 (OR=11.6, 95% confidence interval [CI] [7.8, 17.2]); black race (OR=1.9, 95% CI [1.3, 2.8]); condom use during pregnancy (OR=1.6, 95% CI [1.0, 2.5]); antenatal BV (OR=1.7, 95% CI [1.0, 2.8]); absence of sperm on smear (OR=1.7, 95% CI [1.0, 2.9]); and no history of sexually transmitted diseases (OR=1.6, 95% CI [1.0, 2.5]). Risk score weights were 5 for an elevated vaginal pH and 1 otherwise. The sensitivity and specificity of screening women with scores > or =4 were both 77%; this would involve screening 33% of patients.

Approximately 80% of our BV cases were asymptomatic, emphasizing the need for objective risk assessment. Using six factors, clinicians can identify pregnant women at risk for BV.