Excretion of unconjugated and conjugated progesterone metabolites in pregnancy urine during ampicillin administration

Abstract

Progesterone metabolites were determined in the fractions of unconjugated steroids, steroid glucuronides and steroid mono- and disulphates in urine, pooled daily from a group of pregnant women before, during and after ampicillin administration. Ampicillin administration resulted in a decrease in the excretion of total progesterone metabolites measured on the second day of treatment. It did not effect the urinary excretion of the unconjugated, monosulphated or disulphated progesterone metabolites measured with the exception of 5β-pregnan-3α,20α-diol disulphate. The excretion of 5α — and 5β -pregnan-3α,20α-diol and 3α-hydroxy-5α- and 5β-pregnan-20-one glucuronides were both decreased on the second day of ampicillin administration. However, the decrease in all cases was corrected (or overcorrected) on the subsequent three days. An uncorroborated increase in total progesterone metabolite and individual glucuronide metabolite excretion was obtained on the first day of ampicillin treatment with one of the methods used. Our results do not indicate any factor which could be responsible for the changes induced by ampicillin administration. However, because the effect of ampicillin on the excretion of total progesterone metabolites measured was slight and transitory and, in addition, because it was limited to specific metabolites only, it is more likely that the changes observed during ampicillin administration are attributable to altered progesterone metabolism in the maternal organism (e.g. altered enterohepatic circulation) rather than to possible effects on progesterone synthesis.