Eggs may be released in the morning or at night, there is no fixed time. Ovulation does not depend on the time of day, but can occur at any time within 24 hours on the day of ovulation, either during the day or at night, with some individual variation, and is not fixed. For women who have regular periods, ovulation occurs about 14 days before the onset of menstruation, and during ovulation, there will be a pulling of the leukorrhea and a rise in basal body temperature, etc. Ovulation can also be monitored through ultrasound or ovulation test strips to determine the approximate time of ovulation. If a woman intends to have children, she can choose to have intercourse during ovulation, the egg can survive in the body for a longer period of time, no matter in the daytime or nighttime intercourse, will increase the chances of female fertilization. On the contrary, if there is no requirement for childbearing, good contraception is needed.