Sperm generally survive in the uterus for 2-3 days, beyond which time they lose their ability to fertilize. A woman can ovulate once a month and usually only one mature follicle expels an egg, which can survive for 1-2 days after ovulation. The sperm can survive in the uterus for 2-3 days, so there is a chance of pregnancy for 72 hours after intercourse. If you are preparing for pregnancy, you can arrange intercourse every 72 hours to increase the success rate of conception. If you do not have a pregnancy plan, but have intercourse during ovulation and do not take protective measures in time, you can take oral emergency contraceptives within 72 hours, the efficiency can reach 90% or more. The survival time of sperm varies individually and is closely related to the physical condition of the man and the surrounding environment. Usually, you should pay attention to rest, strengthen sports and exercise, and avoid exposure to toxic and harmful substances.