If a woman has a regular menstrual cycle of 28-30 days, the day of ovulation for a woman is around the 16th day of her menstrual period, which is about 14 days before the next menstrual period. If menstruation is 4 days earlier, the day of ovulation should be on the 12th day of menstruation. Eggs can be discharged from both ovaries in turn, or continuously from one side. The 5 days before ovulation, the day of ovulation and the 4 days after ovulation, adding up to about 10 days, is the ovulation period, and the rest of the time is the safe period. During the ovulation period, intercourse every 2-3 days will greatly increase the chances of conception. However, the safe period is affected by the environment, emotions and other factors, and may not be 100% accurate. If you do not have the requirement to have children, it is better to take safer contraceptive measures such as the ring and condom.