Vaginal pH versus cervical length in the mid‐trimester as screening predictors of preterm labor in a low‐risk population

Abstract

Methods: Prospective cohort study of 316 low-risk pregnant women. Vaginal pH was measured using test gloves for measuring the vaginal acidity, while CL was measured using transvaginal ultrasound. The cut off value for vaginal pH used was 5.0 (95 th centile for our population) whereas shortened CL was defined as < 26 mm (5 th centile for our population).Results: Elevated vaginal pH was found in 4.4% whereas shortened CL was found in 2.8%. The incidence of PTL (< 37 weeks) was 7.2%, and early PTL (< 34 weeks) was 3.4%. Shortened CL is significantly related to PTL (LR weighted by prevalence 2.7, 95% CI 1.1-6.7) but is not to early PTL (LR weighted by prevalence 0.8, 95% CI 0.4-1.8). Elevated vaginal pH is better predictor of PTL (LR weighted by prevalence 3.7, 95% CI 1.3-10.4) and early PTL (LR weighted by prevalence 1.7, 95% CI 1.1-3.1). Conclusion:Elevated vaginal pH has better accuracy in comparison with shortened CL regarding the prediction of early PTL in low risk pregnant women.

Normal vaginal flora, disorders and application of probiotics in pregnancy

“…Abnormal vaginal Xora and vaginal inXammation are recognised risk factors for ascending urogenital infections, and in pregnant women extrauterine infections/ inXammations have been associated with preterm birth (for a comprehensive review see [37]). Accordingly, it has been proposed that an elevated vaginal pH is a good predictor of early preterm labour in women at low risk [38][39][40][41][42]. Our results conWrm the potential usefulness of vaginal pH measurement as is a quick, inexpensive, "bedside" diagnostic test that provides a substitute marker for vaginal health [43].…”

Vaginal fluid PH versus cervical length as a predictor of preterm labor in second trimester of pregnancy .

“…Women with BV based on Nugent score ≥7 (p=0.04) or pH ≥5 (p=0.016), had significantly lower CL than unaffected women; however, all of these effects were null after covariate adjustment. In contrast to our study, another study conducted by Matijevie et al 3 , involved 316 low-risk pregnant women. Elevated vaginal pH was found in 4.4% whereas shortened CL was found in 2.8%.…”

“…Two topics are related to screening for premature labor; bacterial vaginosis (BV) and cervical insufficiency. Both can be diagnosed using simple, safe, well-accepted, reliable, and reproducible methods; and they are potentially treatable 3 . Bacterial vaginosis is a modification of the vaginal flora characterized by a diminished or absent flora of lactobacilli, which increases the vaginal pH, and a significantly increased colonization of several anaerobic or facultative microorganisms 4 .…”

Association between increased antenatal vaginal pH and preterm birth rate: a systematic review

“…In addition, half of the studies are plotted outside the pseudo 95% confidence limits which might be an indication of heterogeneity and possible bias in the study results. At the left side of the funnel plot and at the far right side of the plot, we can distinguish the studies by Garay et al (2011) (blue plus), Bartnicki et al (1996) and Masood et al (2013) (both blue dots) and Matijevic et al (2010) (red cross), which appear as outliers compared to the rest of the studies [23,30,33,55].…”

“…The definition of pathological pH varied across studies with the majority using a threshold of >4.5 (27%, n = 8) [9, 22, 24-27, 30, 40] or ≥5.0 (20%, n = 6) [10,21,31,38,54,55]. The methods to assess the vaginal pH were colour sensitive indicator strips (67%, n = 16) [10, 13, 21, 23-26, 28, 29, 31, 32, 34, 35, 41, 54, 56], colour sensitive test gloves (17%, n = 4) [9,19,37,55], application of vaginal fluid from a swab to a pH microcomputer (8%, n = 2) [20,39] or a combination of these methods (8%, n = 2) [22,36]. Information on the interval of the measurement method was given by nine (30%) studies and included 0.1 [24,35], 0.3 [28,29,36,37,39] and 0.5 [13,54] pH units.…”