The probability of a woman getting pregnant is quite high when she has sex during ovulation. The most basic principle of pregnancy is that the sperm enters the woman’s body and meets the egg inside the fallopian tube, so a woman can only have sperm unite with the egg if the sperm enters the woman’s body near the time of ovulation. If no egg is encountered, the sperm will not enter the woman’s body to cause pregnancy. The sperm can survive inside the fallopian tube for 2-3 days when it enters the woman’s body, and the egg can survive for 12-24 hours after it is expelled. This means that a woman who has intercourse three days before ovulation, or 24 hours after ovulation, has a very high probability of getting pregnant and can become pregnant. There are many factors that can affect a woman’s ability to conceive, not only ovulation, but if the fallopian tube is blocked, the egg cannot pass through the blocked tube and the sperm and egg cannot unite, making conception impossible. If the endometrium is diseased, the sperm and egg cannot enter the uterine cavity and become fertilized. Therefore, the probability of pregnancy during ovulation is high, but it is not 100%, because there are other factors that may affect pregnancy.