Pregnanediol

Pregnanediol, or 5β-pregnane-3α,20α-diol, is an inactive metabolic product of progesterone. A test can be done to measure the amount of pregnanediol in urine, which offers an indirect way to measure progesterone levels in the body.
In 1936, Venning and Browne demonstrated the presence of pregnanediol, specifically the glucuronide of pregnanediol in pregnancy urine. Their study extracted pregnanediol from pregnancy urine and revealed that pregnanediol concentration in urine indicates the amount of progesterone excreted. Since progesterone levels indicate the functionality of a corpus luteum, and pregnanediol concentration represents 40-45% of the progesterone excreted, estimations of pregnanediol reveal the functionality of a corpus luteum. However, pregnanediol concentrations vary with menstrual cycle phases, so it is essential to consider the menstrual cycle phase when examining them. Furthermore, current research has demonstrated that pregnanediol concentration in urine is also a measure of ovarian activity.