Increased inorganic sulfate concentrations in amniotic fluid.

ABSTRACT

We assayed inorganic sulfate by ion chromatography in 49 amniotic fluid samples from pregnancies of 14 to 38 weeks gestation. In second trimester samples (14 to 26 weeks gestation), amniotic fluid sulfate concentrations (317 +/- 22 mumol/L, mean +/- SE; n = 32) were not different from previously reported maternal serum values but were significantly lower (p < 0.001) than in the third trimester (693 +/- 42 mumol/L; n = 16). In third trimester samples, sulfate concentrations were significantly correlated with creatinine and uric acid but not chloride, suggesting that renal excretion may be the major source of the amniotic fluid sulfate in the late stages of gestation.