There is a possibility of pregnancy without contraception if you have intercourse from the start of your period to the tenth day. From the beginning to the tenth day of menstruation, if there is incomplete atrophy of the corpus luteum, the woman may still be in the menstrual period at this time. You can’t get pregnant if you have intercourse during your period, but it’s important to note that menstruation is a special physiological stage when you shouldn’t have sex. If the ordinary menstrual cycle for 30 days of women, its ovulation time for the next menstrual period on the 14th day, from the menstrual period to the 10th day, theoretically has not entered the ovulation period. However, due to the influence of some other factors, ovulation may occur earlier, it may be pregnant. If a woman with a short menstrual cycle has intercourse on the tenth day after the start of her period, ovulation and thus pregnancy may occur. Therefore, if you have intercourse without contraception from the start of your period to the tenth day, you should take a pregnancy test to rule out pregnancy if you experience menopause. In addition, when there is no need for pregnancy, it is important to use contraception in future intercourse to avoid unwanted pregnancy.