D-Gest 10 mg contains Dydrogesterone, a synthetic form of the naturally occurring female hormone progesterone. It is primarily used in the treatment of various menstrual disorders caused by progesterone deficiency, such as irregular menstruation, secondary amenorrhea, and premenstrual syndrome (PMS). It is also used to support early pregnancy in women with a history of recurrent miscarriages or threatened abortion due to low progesterone levels. Dydrogesterone helps regulate the healthy growth and shedding of the uterine lining, supporting a normal menstrual cycle and early pregnancy. Unlike some older synthetic progestins, dydrogesterone is selective in its action and tends to have fewer androgenic or estrogenic side effects, making it a preferred choice in hormone replacement and fertility treatments.