Vaginal and cervical pH measurements in normal pregnancy and preterm labor

Objective: The objective of this study was to determine the mean value of vaginal pH during normal pregnancies and those with preterm delivery and to correlate pH measurements with vaginal bacterial cultures. Methods: We have followed prospectively vaginal pH and vaginal bacteriological measurement in 139 pregnant women during the course of pregnancy. Two groups of patients were selected. A total of 197 vaginal pH measurements were obtained in Group I at intervals of 2-4 weeks. Group II patients (control group) did not have premature labor during pregnancy. Results: Elevated vaginal pH values such as a pH of more than 4.6 introitus or more than 4.9 posterior fornix are due to disturbed vaginal flora and lead to the possibility of preterm labor and prematurity. Gardnerella vaginalis, Trichomonas vaginalis, Candida albicans, Escherichia coli, and Staphylococcus aureus are related to elevated pH values. Clinical screening with pH measurement seemed advantageous. Conclusions: Elevated pH values are due to disturbed vaginal flora (bacterial vaginosis, trichomonas vaginalis, candida, etc.). The vaginal pH may be a useful clinical screening parameter for identification of disturbances of the microflora. We recommend vaginal pH measurement for a quick detection of infection in cases with preterm labor.