The formation of eggs is a long-term process, generally from the embryonic period began to develop, women are born in the ovary generally stored 300,000 ~ 400,000 oocytes, with the role of ovarian secretion of estrogen and progesterone hormones, will be discharged every month a mature egg, the life of a mature egg of about 300 ~ 400, the rest of the oocytes will be self-generated. Eggs are usually discharged about 14 days before the next menstrual period, after ovulation, if combined with sperm will form a fertilized egg, so for women who need to prepare for pregnancy, it is recommended to pay attention to their own body temperature, leucorrhoea, and other changes, and if necessary, can be used to test the ovulation paper or go to the gynecology department of a regular hospital ultrasound to monitor follicle development, in order to increase the chances of conception.