A woman is fertile for up to one day after ovulation, per About.com. An egg is viable for 12 to 24 hours following ovulation, the American Pregnancy Association notes. After that time, unfertilized eggs then disintegrate and are absorbed by the lining of the uterus.
It is possible for sperm to live as long as five days inside a woman's body, according to WebMD. Because of the sperm's longevity, About.com explains that pregnancy can occur if a woman engages in unprotected sex any time between five days before she ovulates to one day after ovulation occurs. The American Pregnancy Association advises that a woman can expect to ovulate between day 11 and day 21 of her menstrual cycle. Some women feel a bit of pain when ovulation occurs, and some women notice slight spotting upon ovulation.