How does ovulation determine when I can get pregnant? Knowing your time of ovulation is crucial to successful conception. Your fertile period starts about 4-5 days before ovulation, and ends about 24-48 hours after it. This is because sperm can live in your body for approximately 4 to 5 days, and the egg can live for 24 to 48 hours after being released. Maximum fertility is reached during the Ovulation