Serum uric acid levels in normal pregnancy with observations on the renal excretion of urate in pregnancy.

Serum uric acid estimations were performed in 106 healthy pregnant women during early, middle, and late pregnancy, using an automated colorimetric method. The mean serum uric acid level was significantly lower during early and middle pregnancy than that of 64 age-matched female controls. The serum uric acid level was not significantly different in late pregnancy from the control group. Studies of the daily urinary urate excretion in 31 pregnant women showed normal urinary urate excretion in early pregnancy and enhanced renal loss of urate in middle and late pregnancy. It appears that the renal clearance of urate in pregnancy is high, especially in the middle period when the serum level is low in spite of the increased production of uric acid by the foetus.