Objectives: Maternal infection, particularly bacterial vaginosis (BV) in pregnancy, is one of the leading causes of adverse perinatal outcomes. The determinants of individual differences in susceptibility, or vulnerability, to maternal infections are poorly understood. This study examines whether chronic maternal stress predisposes women to infection during pregnancy, and if so, whether the effects of chronic stress on infection are independent of other established risk factors.
Methods: We conducted a cross-sectional, clinical prevalence study of chronic maternal stress and BV status in a sample of 454 pregnant women at 14.3+/-0.3 weeks gestation (+/-SEM). BV was diagnosed by Gram-stain of vaginal fluid samples; chronic maternal stress was assessed using the Cohen Perceived Stress Scale. Other established risk factors for BV, including maternal age, race/ethnicity, marital status, SES, and behaviors related to feminine hygiene, sexual practices, and substance use, were measured using a structured interview.
Results: Of the 454 women enrolled in this study, 224 (49%) were BV positive (Nugent score 7-10), 64 (14%) had intermediate vaginal flora (Nugent score 4-6), and 166 (37%) were BV negative (Nugent score 0-3). BV+ women had significantly higher chronic stress levels than BV- women (24.6+/-0.5 vs. 22.2+/-0.6 units (+/-SEM), respectively; t = 3.19; p < .01). Maternal sociodemographic variables (African-American race/ethnicity) and behavioral characteristics (vaginal douching, number of lifetime sexual partners, and use of illicit drugs) also were significantly associated with the presence of BV. After controlling for the effects of these variables, using a multivariable logistic regression model, chronic maternal stress remained a significant and independent predictor of BV status. Women in the moderate-stress group (third quartile) and high-stress (fourth quartile) group were 2.3 times (95% CI = 1.2-4.3) and 2.2 times (95% CI = 1.1-4.2) more likely to be BV+ than women in the low-stress group (bottom quartile).
Conclusions: High levels of chronic stress during pregnancy are associated with bacterial vaginosis. The effect of chronic maternal stress is independent of the effects of other established sociodemographic and behavioral risk factors for BV.