In principle, the egg can survive in the woman’s body for about 3 days, while the egg can survive for 24 hours, but the sperm can only survive for a few minutes outside the body. For women on birth control, it is not recommended to have a safe period because ovulation at any point within three days after intercourse can lead to pregnancy, and ovulation is not constant at a fixed time every month, it is affected by many factors, such as sexual excitement, mood swings, etc., which can lead to early or late ovulation, so the so-called safe period contraception is absolutely undesirable. If a woman wants to prepare for pregnancy, she can monitor ovulation, such as ovulation test paper or body temperature and ultrasound monitoring, generally once before ovulation and once after ovulation is sufficient. It is important to emphasize that sperm need to be renewed, it is not recommended to wait for frequent sex during ovulation without having intercourse all the time, so that the sperm activity may have declined, which may seriously affect the chances of pregnancy, and may also lead to excessive male fatigue, affecting health. So usually you should have intercourse at the right time, 2-3 times a week is recommended. In short, women on contraception are advised to use condoms throughout the safer, and women who want to prepare for pregnancy must relax and not be rushed.