5β-Pregnan-3α-ol-20-one-d4 is a labelled analogue of 5β-Pregnan-3α-ol-20-one (P711300), which is a hyponotic-anaesthetic agent. It is also an intermediate in synthesizing Pregnanediol-d5 3α-O-β-D-Glucuronide (P705142), which is a glucuronide conjugate of Pregnanediol (P705130). Levels of Pregnanediol 3α-O-β-D-Glucuronide can be used to monitor the reproductive status of dairy cows. 3α-O-β-D-Glucuronide can be used (as an alternative to creatine) as a reference to adjust other hormonal markers in study of urinary hormonal profiles in the human menstrual cycle.