Lynestrenol is primarily used in hormonal contraception, often as a component of oral contraceptive pills. It helps prevent pregnancy by inhibiting ovulation, altering the cervical mucus to impede sperm penetration, and modifying the endometrium to reduce the likelihood of implantation. Additionally, it is utilized in hormone replacement therapy (HRT) to manage symptoms of menopause, such as hot flashes and vaginal atrophy, by supplementing estrogen levels. Lynestrenol is also prescribed to treat menstrual disorders like irregular cycles, heavy bleeding, and endometriosis by regulating hormonal imbalances. In some cases, it is used to support pregnancy in women with a history of recurrent miscarriages by maintaining a stable hormonal environment.