What is "segesterone"

Segesterone ( INN, USAN)1, also known as 17α-hydroxy-16-methylene-19-norprogesterone or as 17α-deacetylnestorone, is a steroidal progestin of the 19-norprogesterone group that was never marketed.2 An acetate ester, segesterone acetate, better known as nestorone or as elcometrine, is marketed for clinical use. Segesterone acetate produces segesterone as a metabolite.