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 R4.7 or pH R5 by itself was not associated with LBW or prematurity.
Conversely, combination of pH R5 and high sialidase activity demonstrated OR 17 (CI 1.8-
150) 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 (CI 1.9-542) for preterm at !32 weeks’ gestation. The combination
of pH R5 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 (CI 0.6-150) for preterm at !35 weeks’; and OR 35
(CI 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 R2500 g at birth.
