If you use ejaculation during ovulation, the chance of pregnancy can reach 20%, because the male partner may have a small amount of prostatic fluid before ejaculation, and prostatic fluid also contains sperm, and if the sperm is more active, a small amount of sperm can enter the cervix and combine with the egg waiting in the abdomen of the fallopian tube to form a fertilized egg. Therefore, it is not recommended to use in vitro ejaculation as a contraceptive method during ovulation. Instead, condoms or short-acting contraceptive pills should be used continuously from the 5th day of menstruation, which are simple, safe and reliable, and the contraceptive rate can reach more than 90%. In addition, the application of emergency contraceptive pills is not recommended during ovulation, because emergency contraceptive pills are also not reliable during ovulation, and the side effects of emergency contraceptive pills are relatively large and can affect menstruation and cause menstrual disorders.