Preventing the fertilization of the egg can be done by oral emergency contraceptive pills, oral mifepristone, placing a contraceptive ring and so on. 1. Oral emergency contraceptive pills: commonly used, such as compound levonorgestrel tablets, etc., its mechanism is to change the intrauterine environment, so that the development of the uterine lining and the development of the embryo is not synchronized, so as to achieve the purpose of preventing the implantation of the fertilized egg, it is recommended to take within 72 hours after fertilization. 2. Oral Mifepristone: Mifepristone is an anti-progestin agent, which antagonizes progesterone and thus makes the synthesis of zona pellucida hydrolysis enzyme impaired, and the zona pellucida can’t disappear smoothly, thus the fertilization of the egg fails. 3. Placement of contraceptive ring: By placing a contraceptive ring in the uterine cavity, it can have a direct toxic effect on the fertilized egg, thus preventing the fertilized egg from implanting. If you need to prevent the fertilization of the egg, it is recommended that you use drugs or place a contraceptive device under the guidance of your doctor and according to your actual situation.