Transplantation after 5-7 weeks of a descending artificial cycle. During the luteal phase of menstruation, which is about 20 days, the descending drug GnRH-a 1.8mg or 3.75mg is started, and the artificial cycle starts after two weeks with 1.8mg and after four weeks with 3.75mg. The artificial cycle starts with oral GnRH-a, the length of time is related to the thickness of the endometrium, it takes about 12-23 days, usually about two weeks, when the endometrium is ≥7mm and estradiol is >100pg/mL, progesterone is started to convert the endometrium by intramuscular injection, and transplantation starts after 3-5 days. So the whole process of descending takes 2-4 weeks, and the manual cycle is about 2 or 3 weeks. Progesterone conversion of the endometrium takes 3 or 5 days, adding up to about 5-7 weeks.