Increased inorganic sulfate concentrations in amniotic fluid.

Area of Science:

• Obstetrics and Gynecology
• Biochemistry
• Perinatal Medicine

Background:

• Inorganic sulfate is an essential metabolite with roles in fetal development.
• Understanding amniotic fluid composition is crucial for monitoring pregnancy health.

Purpose of the Study:

• To quantify inorganic sulfate concentrations in amniotic fluid across different gestational ages.
• To investigate the relationship between amniotic fluid sulfate and other biochemical markers.

Main Methods:

• Ion chromatography was used to assay inorganic sulfate in 49 amniotic fluid samples.
• Samples were collected from pregnancies ranging from 14 to 38 weeks gestation.

Main Results:

• Second-trimester amniotic fluid sulfate levels (317 ± 22 μmol/L) were comparable to maternal serum values.
• Third-trimester amniotic fluid sulfate levels (693 ± 42 μmol/L) were significantly higher than in the second trimester (p < 0.001).
• Third-trimester sulfate concentrations correlated with creatinine and uric acid, but not chloride.

Conclusions:

• Amniotic fluid sulfate concentrations increase substantially during the third trimester.
• Fetal renal excretion is likely the primary contributor to amniotic fluid sulfate in late gestation.