Didrogestrel should be started on the 14th day after menstruation, i.e. on the first day of menstrual bleeding and counting backwards to the 14th day, which is around the time of ovulation. In the case of uterine bleeding due to abnormal ovarian function, it is more appropriate to start using dydrogesterone at the time of ovulation in order to correct the abnormal uterine bleeding caused by the lack of progesterone in the body. In the case of other abnormal uterine growths, it is sometimes considered to be started on the first day of the menstrual cycle. If the purpose is to assist in pregnancy, the application of detrofloxacin can be considered after ovulation, and the dose can be increased accordingly after a successful pregnancy is confirmed.