If you have your period on May 8th and have intercourse on May 16th, you will know if you are pregnant or not about 10 days after the intercourse. For women with regular menstrual cycles, when they have their period on May 8, ovulation usually occurs around May 22, and when they have intercourse on May 16, they are in the safe period. Although the chances of getting pregnant are relatively low, there is still a possibility of pregnancy, and a blood HCG (human chorionic gonadotropin) test can be performed about 10 days after intercourse to determine whether or not you are pregnant. For women who want to have children, they can be guided by their doctors to have intercourse by calculating the ovulation period to improve their chances of conceiving. However, if you do not want to have children, you need to choose safe and effective contraceptive measures, such as placing an intrauterine device (IUD), condoms and oral short-acting contraceptive pills, to avoid unwanted pregnancies and to minimize the damage caused by abortion.