Trimegestone

Trimegestone (INN) (brand name Ondeva), also known as 21-hydroxypromegestone, is a 19-norprogesterone derivative and steroidal progestin which was introduced in France in 2001 and is used as a hormonal contraceptive and in hormonal replacement therapy for postmenopausal symptoms. It is a very potent and pure progestogen, lacking activity at other steroid hormone receptors. Trimegestone has been described as both "fourth generation" and "second generation" (due to the use of different progestin generational schemes; in any case, it is considered to be of the most recent generation).