There is usually no optimal time to break the egg injection because ovulation is not consistent from woman to woman. Generally, the egg-breaking injection is given after the follicle matures during the woman’s ovulation period. Infertility can be caused by a woman’s follicles not ovulating when they are mature, at which point she should receive an egg-breaking injection, which is made of human chorionic gonadotropin. Before the injection, you need to decide the specific injection time according to the size of the egg, usually choose after the follicle has fully developed and matured, you can take the injection in the afternoon of the same day. It is generally considered that if the follicle has a maximum diameter of more than 20mm, it is a mature follicle, and it is suitable for the injection to break the egg. However, there are individual differences, some women’s follicles will be discharged when their diameter reaches 15mm, while some women’s follicles will not be discharged until their diameter reaches 25mm, which should be clarified by ultrasound. The injection should follow the doctor’s instructions strictly and should not be changed on its own. After the injection, coitus should be arranged in a timely manner and the frequency of coitus should be increased appropriately in order to improve the chances of conception.