Combination of vaginal pH with vaginal sialidase and prolidase activities for prediction of low birth weight and preterm birth.

Objective: The purpose of this study was to assess if easy to measure vaginal fluid biomarkers are predictive for low birth weight (LBW, < 2500 g), very LBW (VLBW, <1500 g), spontaneous preterm at <37 weeks' gestation, and total preterm, deliveries (at <37, <35, <32 weeks' gestation). Study design: Low and high cutoffs for vaginal fluid pH, sialidase, and prolidase activities were examined in a nested case-control study of 579 Danish women (from a study population of 2846 women) with samples collected at mean 17 weeks' gestation. One hundred sixteen LBW (17 VLBW), 117 preterm deliveries (85 spontaneous), and 418 normal term deliveries were analyzed. Results: Vaginal pH greater than or equal to4.7 or pH greater than or equal to5 by itself was not associated with LBW or prematurity. Conversely, combination of pH 5 and high sialidase activity demonstrated OR 17 (CI 1.8150) for LBW OR 31 (CI 1.8-516) for VLBW; along with OR 18 (CI 1.6-204) for preterm at <35 weeks'; and OR 31 (Cl 1.9-542) for preterm at <32 weeks' gestation. The combination of pH greater than or equal to5 and high prolidase activity demonstrated OR 13 (CI 1.3-122) for LBW; OR 33 (CI 2.0-553) for VLBW, as well as OR 9.2 (Cl 6.6-150) for preterm at <35 weeks'; and OR 35 (Cl 2.0-586) for preterm at <32 weeks' gestation. In this population, no woman having high sialidase and high prolidase activity had a term birth, or a baby weighting 2500 g at birth. Conclusion: In this Danish population, inid-gestation findings of vaginal fluid elevated pH with sialidase and/or prolidase were associated with LBW, VLBW, and early preterm at <35 or <32 weeks' gestation. (C) 2005 Elsevier Inc. All rights reserved.