EXCRETION OF 6-OXYGENATED METABOLITES OF PROGESTERONE AND 5β-PREGNANE-3α,17α,20α-TRIOL DURING PREGNANCY

Abstract

SUMMARY: The excretion of pregnanediol, pregnanetriol and the 6-oxygenated metabolites of progesterone by fifteen women has been measured throughout pregnancy. During the first trimester the level of excretion of the 6-oxygenated metabolites varied from 0·4 to 2·2 mg./day and at the end of pregnancy the range was from 3·5 to 11·6 mg./day. During the last 6 weeks of pregnancy, pregnanediol excretion was relatively constant, whereas in seven of the patients the excretion of the 6-oxygenated metabolites continued to increase. Except at the end of pregnancy there was a close correlation between the 6-oxygenated metabolites and pregnanediol excretion. The results suggest that the 6-oxygenated metabolites and pregnanediol have the same precursor and that little, if any, of a 6-oxygenated progesterone is secreted during pregnancy. There appears to be little increase in pregnanetriol excretion during pregnancy; six of the subjects showed a significantly higher excretion in the third trimester compared with the first trimester of pregnancy, but the values were not outside the normal range for non-pregnant subjects. The specificity of the method of Fotherby & Love (1960) for the estimation of pregnanetriol was examined when applied to pregnancy urine. Between 1·1 and 2·4 % of administered progesterone was excreted as the 6-oxygenated metabolites. In only one of five subjects was pregnanetriol excretion increased after progesterone administration.