In general, the sperm is ejaculated into the female vagina, into the female genitalia, more than 72 hours can still be fertilized, but the chances are very small, if it is outside the body, and did not enter the female ovaries, generally has no ability to fertilize. Sperm survival time in the body is generally not more than 72 hours, 72 hours later, the sperm may lose their vitality the chances of fertilization will be smaller, if you want to get pregnant, it is best to cohabitate in the period of ovulation, the chances of pregnancy will be higher, if you do not want to get pregnant, it is recommended to do a good job of contraceptive measures. In daily life, eat more fresh fruits and vegetables, ban smoking and alcohol, often exercise to improve personal physical fitness, control the frequency and time of coitus, so as to increase the chances of fertilization.