Renal prostaglandins E2 and F2 alpha throughout normal human pregnancy

Twenty-five normal pregnant women were studied sequentially at 4-week intervals, beginning from weeks 8-16 until delivery. In eighteen women the study was repeated 6 weeks after delivery. The 24-h urinary excretion of PGE2 and PGF2 alpha, plasma renin activity (PRA), plasma aldosterone and fractional excretion of sodium (FENa) were measured at each visit. PGE2 and PGF2 alpha increased progressively throughout pregnancy (867 +/- 81 and 1048 +/- 94 ng 24 h-1 respectively, before week 15 and 1581 +/- 175 and 2625 +/- 305 ng 24 h-1, respectively, after week 35) and returned to normal values 6 weeks after delivery (748 +/- 107 and 1503 +/- 165 ng 24 h-1, respectively). PRA and aldosterone increased in a similar fashion, but values of prostaglandins did not correlate with those of PRA or aldosterone. PGE2 correlated directly with FENa but this correlation was weak. These results may suggest that tubulo-interstitial prostaglandins play a role in the regulation of sodium homeostasis during pregnancy.