ABSTRACT
The principal metabolite of progesterone is pregnanediol which is excreted in urine conjugated with glucuronic acid. In general, the urinary excretion of this metabolite mirrors the cycle of corpus luteum activity rising shortly after ovulation and declining at the time of corpus luteum involution. In pregnant women assays of urinary pregnanediol and pregnanolone have found a place in monitoring progesterone production. The excretion of these metabolites shows a wide variation among individuals; nevertheless, there is a definite pattern in the increments of excretion as the pregnancy advances. During early pregnancy up to the 20th week of gestation, urinary pregnanetriol excretion remains low. As the pregnancy advances, a continuous increase in urinary pregnanetriol is observed and near term the excretion may range from 4 to 13 mg/24 hr. The rise in pregnanetriol during normal pregnancy shows some parallelism with urinary total estrogen and estriol excretion, thus reflecting the function of the fetal component of the fetoplacental unit.
