17-hydroxyprogesterone

17α-hydoxy progesterone (17α-OHP) is produced by the adrenal cortex and gonads, and its progesterone activity is very low. 17α-OHP is 21-hydroxylated to produce cortisol precursor compound S (CpS). 17α-OHP has a circadian rhythm consistent with the adrenal cortisol. The 17α-OHP concentration of adult women of childbearing age changes with the menstrual cycle, and the luteal phase is higher than the follicular phase. The fetus, placenta, and adrenal glands can produce large amounts of 17α-OHP during pregnancy. After 32 weeks of gestation, the concentration of 17α-OHP increased sharply until delivery, and 17α-OHP was also present in the umbilical cord blood of newborns.