Abstract
The renal clearance of amylase, expressed as a proportion of simultaneous creatinine clearance (Cam/-Ccr), was determined in 131 women in various stages of pregnancy. No abnormal serum levels of amylase were found. A moderate but significant increase in Cam/Ccr occurred during the last 15 weeks of pregnancy. Possible causes for this change were investigated in smaller groups of subjects. No increase in rapidly cleared isoamylase could be detected. No modification in renal tubular handling of protein could be evidenced, as assessed by measurements of the renal clearance of β2 microglobulin, expressed as a proportion of simultaneous creatinine clearance. An increased glomerular permeability to amylase probably accounts for elevated Cam/Ccr in pregnancy.