 OHPA is a progestin, or a synthetic progestogen, and hence is an agonist of the progesterone receptor, the biological target of progestogens like progesterone.OHPA was discovered in 1953 and was introduced for medical use in 1956.OHPA has been used in the treatment of a variety of gynecological disorders, including secondary amenorrhea, functional uterine bleeding, infertility, habitual abortion, dysmenorrhea, and premenstrual syndrome.