Follow-up of other babies exposed in utero to vaginal progesterone would be helpful in determining whether the increased rate of some renal, gastrointestinal, and respiratory complications is a real effect or a type I error. The journal reviewer Richard Lehman, senior Research Fellow at the Department of Primary Health Care at the University of Oxford, made the following notable commentary on the OPPTIMUM study: "Thats it. This story is ended, and nobody need ever use vaginal progesterone again to prevent preterm birth. "A Cochrane review on progestogen for preventing preterm birth concluded that there was little evidence that either vaginal or intramuscular progesterone helped to reduce the risk of preterm birth in women with a multiple pregnancy. Gynecological disorders
OHPC is used in the treatment of threatened miscarriage, gynecological disorders such as dysmenorrhea, premenstrual syndrome, fibrocystic breast disease, adenosis, and breast pain. In addition, OHPC is used in the treatment of endometrial cancer and has been found to be significantly effective in extending life in both premenopausal and postmenopausal women with the disease. The medication was used widely in the 1950s through the 1970s for such indications, but OHPC more recently has received the most attention in the prevention of preterm birth. Birth control
OHPC is available in combination with estradiol valerate as a once-monthly combined injectable contraceptive in a few countries. Other uses
OHPC has been used as a component of menopausal hormone therapy in women.OHPC has been used to treat benign prostatic hyperplasia in men, although evidence of effectiveness is marginal and uncertain.
However, in women pregnant with twins rather than a singlet, the elimination half-life of OHPC was found to be shorter than this, at 10 days. OHPC has been detected in pregnant women up to 44 days after the last dose. Elimination
OHPC is eliminated 50% in feces and 30% in urine when given by intramuscular injection to pregnant women. Both the free steroid and conjugates are excreted by these routes, with the conjugates more prominent in feces. Veterinary
The pharmacokinetics of OHPC in various ungulates including cattle, buffalo, sheep, and goat have been studied. Time–concentration curves
Chemistry
OHPC, also known as 17α-hydroxyprogesterone caproate or as 17α-hydroxypregn-4-ene-3,20-dione 17α-hexanoate, is a synthetic pregnane steroid and a derivative of progesterone. It is specifically a derivative of 17α-hydroxyprogesterone with a hexanoate (caproate) ester at the C17α position. Analogues of OHPC include other 17α-hydroxyprogesterone derivatives such as algestone acetophenide (dihydroxyprogesterone acetophenide), chlormadinone acetate, cyproterone acetate, hydroxyprogesterone acetate, hydroxyprogesterone heptanoate, medroxyprogesterone acetate, and megestrol acetate, as well as the caproate esters chlormadinone caproate, gestonorone caproate (norhydroxyprogesterone caproate), medroxyprogesterone caproate, megestrol caproate, and methenmadinone caproate. Synthesis
Chemical syntheses of OHPC have been described. : 6

History
Along with hydroxyprogesterone acetate, OHPC was developed by Karl Junkmann of Schering AG in 1953 and was first reported by him in the medical literature in 1954. It was reportedly first marketed in Japan in 1954 or 1955, and was subsequently introduced as Delalutin in the United States in 1956. Due to its much longer duration than parenteral progesterone, OHPC had largely replaced progesterone in clinical practice by 1975.