Pregnancy can occur just 4 days after the menstruation, this is due to the fact that this is very much related to the patient’s menstrual cycle, as well as to the time when the menstruation comes. In the case of a 25-day period, the period is on the body for 7 days, and 4 days past the period is already on the 11th day of the menstrual cycle. In such a woman, the menstrual cycle is 25 days, and ovulation is around the 11th day of the period. In this case, if you have sexual intercourse, you can still get pregnant. So for a woman with a short menstrual cycle and a long menstrual period, her safe period is very little. Such a patient would be better off not using the method of counting safe periods for contraception, and would normally be better off using condoms or taking short-acting oral contraceptives.