17-Hydroxyprogesterone is a C-21 steroid hormone produced during the synthesis of glucocorticoids and sex steroids. As a hormone, 17OHP also interacts with the progesterone receptor.It is derived from progesterone via 17-hydroxylase, a P450c17 enzyme, or from 17-hydroxypregnenolone via 3β-hydroxysteroid dehydrogenase/Δ5-4 isomerase.

17-Hydroxyprogesterone is a natural progestin, and in pregnancy increases in the third trimester primarily due to fetal adrenal production. This hormone is primarily produced in the adrenal glands and to some degree in the gonads, specifically the corpus luteum of the ovary.17-Hydroxyprogesterone is not the same compound as 17-hydroxyprogesterone caproate. 17-Hydroxyprogesterone caproate is a synthetic (artificial) hormone that is similar in structure to medroxyprogesterone acetate and megestrol acetate.