The present invention is directed to novel heteroatom containing tetracyclic derivatives, pharmaceutical compositions containing them and their use in the treatment of disorders mediated by one or more estrogen receptors. The compounds of the invention are useful in the treatment of disorders associated with the depletion of estrogen such as hot flashes, vaginal dryness, osteopenia and osteoporosis; hormone sensitive cancers and hyperplasia of the breast, endometrium, cervix and prostate; endometriosis, uterine fibroids, osteoarthritis and as contraceptive agents, alone or in combination with a progestogen or progestogen antagonist.