C21H28O2 11-Dehydroprogesterone 7,8-Dihydrocannabinol Demegestone Dydrogesterone Ethisterone Guggulsterone Levonorgestrel Norgestrel Pregna-4,20-dien-3,6-dione Tetrahydrogestrinone Tibolone Trimethyltrienolone Δ4-Tibolone