If your period is delayed by one week every month, it means that your period is still regular. Ovulation is calculated 14 days before the next menstrual period, four days before and three days after the day of ovulation, a total of 8 days, which is the ovulation period. If you plan to get pregnant, you should schedule intercourse during the ovulation period, for example, 3 times in 8 days, spacing each intercourse apart, to increase your chances of getting pregnant. If you are not planning to get pregnant and have sex during ovulation, it is recommended that you wear a condom to give birth control, and that you use a condom throughout your sex life, and that you check if the condom is expired or broken before using it.