The safe period for women is during the follicular development phase and the luteal atrophy phase of the follicle, i.e. the 3 days before the clean period to the start of ovulation, and the first day after ovulation to the day before the next menstrual period. After the onset of puberty, women generally have an egg that matures every month. The development of the egg is usually preceded by the follicular phase, the ovulatory phase and the luteal phase, and the ovulation phase is when the egg is expelled, so it is easier to get pregnant during this period. Some women choose to have intercourse for contraception at this time because the chances of conception during the safe period are low. However, if a woman has an irregular life, often stays up late, is tired, or has mood swings, her ovulation period may be inaccurate, so it is not recommended for such patients to use safe intercourse for contraception. It is recommended to use condoms, birth control rings and other methods of contraception. When a woman has delayed menstruation after intercourse or has early pregnancy reactions such as nausea or vomiting, she should go to the hospital to check if she is pregnant.