Methods for treating uterine fibroids, endometriosis, adenomyosis, or heavy menstrual bleeding in a subject, which include administering to the subject from 10 mg to 60 mg per day of N-(4-(1-(2,6-difluorobenzyl)-5-((dimethylamino)methyl)-3-(6-methoxy-3-pyridazinyl)-2,4-dioxo-1,2,3,4-tetrahydrothieno[2,3-d]pyrimidin-6-yl)phenyl)-N′-methoxyurea, and from 0.01 mg to 5 mg per day of a hormone replacement medicament. The present disclosure has methods for reducing menstrual bleeding in a subject, reducing bone mineral density loss in a subject caused by administering a GnRH antagonist to the subject, suppressing sex hormones in a subject, reducing vasomotor symptoms or hot flashes in a subject, and reducing symptoms of decreased libido in a subject having uterine fibroids, endometriosis, or adenomyosis. Further provided are methods of maintaining blood glucose profile, maintaining lipid profile, and/or maintaining bone mineral density in a pre-menopausal woman being treated for one or more conditions or symptoms of endometriosis, adenomyosis, uterine fibroids, or heavy menstrual bleeding; and methods of contraception and treating infertility.