Just after menstruation is the safe period. The safe period, as the name suggests, is compared with the danger period, that is, the ovulation period, before and after the ovulation period to increase the number of intercourse will increase the chances of pregnancy. Safe period is not an effective form of contraception because ovulation is not only affected by the hypothalamus-pituitary-ovarian axis, but also by some external influences, so if you do not have a short-term fertility requirements, a simpler form of contraception is to use a condom. For women younger than 40 years old, you can also choose oral short-acting contraceptive pills, which, in addition to being an effective contraceptive, can also prevent endometrial hyperplasia, treat irregular vaginal bleeding, prevent the regrowth of endometrial polyps, and treat dysmenorrhea.