If your period is regular, you can have intercourse two days before your period, and you will basically not get pregnant at this time, so the chances of getting pregnant without using contraception are very small. It is recommended that in daily life, if you usually have regular periods, you can use a safe period for contraception. However, menstruation is affected by environmental factors and emotions, if you stay up late, often insomnia and anxiety, it can also cause endocrine disorders and cause irregular menstruation, once menstruation becomes irregular, the time of ovulation will definitely change, and using a safe period contraception may cause pregnancy. Therefore, only in the case of normal, regular menstruation can use the safety period contraception, once external factors affect the menstruation, the safety period is not safe, it is advisable to use condoms contraception.