Urinary thiosulfate level in pregnant women

Area of Science:

• Nephrology
• Obstetrics
• Biochemistry

Background:

• Renal colic is a common cause of hospitalization in pregnant patients.
• Pregnancy typically increases excretion of crystallization inhibitors, a protective mechanism against urolithiasis.
• Urinary thiosulfate has shown protective effects against calcium stone formation and increases during pregnancy.

Purpose of the Study:

• To measure urinary thiosulfate levels in pregnant patients during the third trimester and postpartum.
• To assess if thiosulfate acts as a lithogenic protective agent during pregnancy.

Main Methods:

• Collected 24-hour urine samples from pregnant patients during the third trimester and 6 weeks postpartum.
• Analyzed urinary thiosulfate concentrations in samples from a cohort of 14 pregnant women.
• Controlled for diet and monitored for new stone formation.

Main Results:

• No statistically significant difference in urinary thiosulfate levels was observed between the third trimester, postpartum, and post-lactation stages (p = 0.62).
• Urinary thiosulfate levels were similar in patients who formed stones during pregnancy compared to those who did not.
• Average urinary thiosulfate levels were 12.1 µmol/day in the third trimester, 11.1 µmol/day postpartum, and 16.1 µmol/day post-lactation.

Conclusions:

• Endogenous urinary thiosulfate levels remain stable from the third trimester of pregnancy through the postpartum period in women on a standardized diet.
• The findings do not support urinary thiosulfate as a pregnancy-augmented lithogenic protective factor.