The use of progesterone before IVF transplantation is mainly to supplement progesterone, so that the female endometrium has a proliferative phase into a secretory phase, in preparation for the fertilization of the egg. Normal natural conception of women, after the end of menstruation is mainly increased levels of estrogen, estrogen can promote the proliferation of the endometrium, making the endometrium thicker, after ovulation, the female corpus luteum mainly secretes estrogen and progesterone, with progesterone as the main progesterone, progesterone can make the value-added endometrium into the secretory phase, so that the endometrium is further thickened, blood vessels thickened, blood circulation is rich, and it can lay a solid foundation for the implantation of a fertilized egg. It can lay a solid foundation for the fertilized egg to implant. At the same time, progesterone can reduce the sensitivity of the uterus, so that the fertilized egg will not cause uterine contractions that can lead to miscarriage when it is deposited. Fertilized egg as a foreign body, in the female body is easy to cause rejection reaction, progesterone can reduce the sensitivity of the uterus, for the fertilization of the egg and the growth of a very good protective effect.