Definition: Pregnenes with one double bond or more than three double bonds which have undergone ring contractions or are lacking carbon-18 or carbon-19..
tibolone [ Berenguer Infale brand of tibolone,Boltin,Livial,Liviella,Org OD 14,Org OD14,Organon brand of tibolone,tibilone ] used in prevention of postmenopausal osteoporosis