After the follicle is discharged from the surface of the ovary, it usually survives for 1 to 2 days, after which it liquefies and loses its ability to be fertilized. Ovulation usually occurs about 14 days before the onset of menstruation. The follicle is discharged from the surface of the ovary and usually survives for 1 to 2 days, and its ability to be fertilized is strongest within 24 hours of ovulation. After 2 days of ovulation, if fertilization does not occur, the follicle liquefies and thus loses its ability to be fertilized. Since the follicle can survive for 1 to 2 days after it is discharged from the surface of the ovary, if you want to increase the probability of conception, you can start having intercourse three days before the day of ovulation. However, if you have intercourse on the day of ovulation, the egg may liquefy and lose its ability to be fertilized before the sperm and egg meet.