Sperm survival time varies in different parts of a woman’s body, and the length of sperm survival time has an important relationship with fertility. The survival time of sperm in the vagina is about two hours after intercourse. Normally, two hours after intercourse, 90 percent will die, and after 36 hours, even the dead ones will be invisible. In the female vagina, the higher the acidity, the faster the death. The sperm survives at the cervix for no more than three days. Fifteen minutes after intercourse, sperm are found in the cervical mucus. One hour later, sperm enter the inner opening and can be found in the uterine cavity. Six hours later, the cavity is full of active sperm. Twelve hours later, five-sixths of the sperm survive. Thirty-six hours later, one-fourth of the sperm survive, and after three days, there are no live ones, but there are some individual sperm that survive for a particularly long time. The survival time of an egg is usually twenty-four hours, and sperm survive longer in a woman’s body than an egg. Sperm can survive in the fallopian tube for up to 35 days. There are active sperm 14 hours after intercourse, and sometimes there are still live sperm after 35 days, usually at 14 days when they are most active, some entering the abdominal cavity and some returning to the uterine cavity.