If no reliable contraceptive method is used during intercourse and sperm enters the vagina, this situation can easily lead to unwanted pregnancy if it happens to be ovulation. In order to avoid unwanted pregnancy, the following methods of emergency contraception can be used: 1. Emergency contraceptive pills, such as mifepristone and yutin, can be used within 72 hours of intercourse, and the contraceptive effect can reach more than 85%, but this drug may affect endocrine secretion and irregular vaginal bleeding. 2. If there is a requirement for long-term contraception, an intrauterine IUD. Within 5 days of intercourse, the IUD can be used for emergency contraception, and the IUD can be more than 95% effective, but it needs to be operated by a doctor in a hospital. In addition, some pregnant women may be uncomfortable with the IUD, which may cause vaginal bleeding and menstrual disorders.