Vaginal fluid pH, cervicovaginitis and cervical length in pregnancy

The purpose of this prospective study was to determine the possible association among vaginal fluid pH, cervicovaginitis and cervical length in singleton pregnancies at 16-22 weeks of gestation.

A total of 240 asymptomatic singleton pregnancies at 16-22 weeks of gestation were included to the study. Vaginal fluid pH was determined using pH paper in a sterile speculum examination, and cervical length was examined by transvaginal ultrasonographic measurement. Vaginitis was diagnosed by pH determination and wet mount smear; cervicitis was diagnosed by cervical examination. Patients were followed to delivery and hospital records were reviewed to extract obstetric information. Preterm delivery was defined as delivery at or prior to 36 weeks of gestation. Abnormal pH was defined as a pH of > 5.0. Patients with cervicovaginitis (n = 72) were compared with those without any trace of infection (n = 60).

The mean gestational age was 20.3 +/- 1.4. We found an significant association among cervicovaginitis, cervical length and vaginal pH. There was a significant correlation between an elevated vaginal pH (> 5.0) and a shortened cervical length (r = -0.59, p < 0.001). Vaginal fluid pH > 5.0 was associated with increased risk of preterm delivery (OR 4.3, 95% CI 2.0, 9.3; p = 0.001) as well as delivering an infant of less than 2,500 g (OR 4.0, 95% CI 1.4, 11.0; p = 0.009).

Elevated vaginal fluid pH in women at 16-22 weeks of gestation seems to be associated with a decreased cervical length and increased risk of preterm delivery.