Aldosterone and corticosterone in amniotic fluid during various stages of pregnancy

Concentrations of unconjugated aldosterone and corticosterone were measured in amniotic fluid (AF) at different stages of pregnancy. At 9–20 weeks gestation the mean AF level of aldosterone was 14.4±0.7 ng/dl, and of corticosterone 82.9±6.4 ng/dl. Both showed the same pattern during pregnancy, with a rise in AF levels in the last few weeks. At 28–40 weeks gestation the mean AF aldosterone level was 25.5±2.0 ng/dl and the mean AF corticosterone was 218.3±26.6 ng/dl.