Used in hormone therapy to support the luteal phase in women with progesterone deficiency, helping to maintain early pregnancy and reduce the risk of miscarriage. Commonly prescribed for menstrual disorders such as irregular cycles, heavy bleeding, and endometriosis due to its ability to regulate the endometrial lining. Also used in combination with estrogen in hormone replacement therapy for menopausal women to protect the uterus from overstimulation by estrogen alone. Its oral bioavailability and favorable safety profile make it a preferred option in fertility treatments and assisted reproductive technologies.