Elevated vaginal pH in the absence of current vaginal infection, still a challenging obstetrical problem

To assess the association of vaginal pH ≥ 5 in the absence of vaginal infection with systemic inflammation and adverse pregnancy outcome.

Four-hundred sixty pregnant women completed the study, upon enrollment Vaginal pH was measured for all women, maternal and umbilical sera were obtained for determining C-reactive protein (CRP) and uric acid levels. Umbilical blood was tested for gas parameters, 1 and 5 min Apgar scores, the need for neonatal resuscitation and neonatal intensive care unit (NICU) admission were recorded.

Elevated vaginal pH was significantly associated with preterm birth (odds ratio (OR), 2.23; 95% confidence interval (CI), 1.04-4.76), emergency cesarean section (OR 2.57; 95% CI 1.32-5), neonatal resuscitation in the delivery room (OR 2.85; 95% CI 1.1-7.38), elevated cord base deficit (OR 8.01; 95% CI 1.61-39.81), low cord bicarbonate (OR 4.16, 95% CI 1.33-12.92) and NICU admission (OR 2.02; 95% CI 1.12-3.66). Increased vaginal pH was also significantly associated with maternal leukocytosis, hyperuricemia and elevated CRP levels in maternal and umbilical sera.

Elevated vaginal pH in the absence of current vaginal infection still constitutes a risk for adverse pregnancy outcome which is mediated by systemic inflammatory response.