Dydrogesterone, as a progestogen, can inhibit contractions and facilitate intrauterine growth and development of the embryo and fetus, as well as reduce the excitability of the smooth muscle of the uterus and decrease the sensitivity of the uterus to contractile hormones, thus facilitating the continuation of pregnancy. Therefore, based on the above pharmacological effects, dydrogesterone can be used as a contraceptive drug during intrauterine pregnancy. When used as a contraceptive, dydrogesterone is mainly used during the luteal phase and early intrauterine pregnancy, and there are usually no significant contractions. Dydrogesterone mainly increases the tolerance of the placenta of the uterus, facilitating embryo implantation and increasing the blood supply to the placental area of the uterus, so that the fetus can continue to grow and develop smoothly.