Mestranol is primarily used in combination with other hormones in oral contraceptive pills to prevent pregnancy. It works by inhibiting ovulation, altering the cervical mucus to impede sperm penetration, and modifying the endometrium to reduce the likelihood of implantation. Additionally, mestranol has been utilized in hormone replacement therapy to alleviate symptoms associated with menopause, such as hot flashes and vaginal dryness. It is also employed in the treatment of certain menstrual disorders, including irregular periods and severe menstrual cramps, by regulating hormonal imbalances.