 Dydrogesterone, also known as 6-dehydro-9β,10α-progesterone or as 9β,10α-pregna-4,6-diene-3,20-dione, is a synthetic pregnane steroid and a derivative of progesterone and retroprogesterone (9β,10α-progesterone).Retroprogesterone derivatives like dydrogesterone are analogues of progesterone in which the hydrogen atom at the 9th carbon has been switched from the α-position (below the plane) to the β-position (above the plane) and the methyl group at the 10th carbon has been switched from the β-position to the α-position.This reversed configuration in dydrogesterone results in a "bent" spatial geometry in which the plane of rings A and B is orientated at a 60° angle below the rings C and D. Dydrogesterone also has an additional double bond between the C6 and C7 positions (4,6-dien-3-one configuration).