The term “vacation” usually stands for menstruation. For women who usually have regular periods, it is safer to have intercourse three days before menstruation, while it may not be safe if a woman has irregular periods. If a woman’s menstrual cycle is relatively regular and lasts about 28 days, it is safer to have intercourse three days before menstruation. This is mainly because a woman with regular menstrual cycle usually ovulates 14 days before menstruation, and three days before menstruation when ovulation has been completed, there is no egg discharged at this time, so the chances of getting pregnant are smaller. If a woman’s menstruation is usually irregular and often delayed, this situation is not safe, because when a woman’s menstruation is delayed, ovulation is also delayed, and it is possible that she is ovulating three days before her menstruation, and if she has intercourse at this time, the sperm and the egg will meet, and then an unplanned pregnancy may occur. Women’s menstruation is affected by emotions, environment and other aspects, so even for women with regular menstrual cycles, intercourse three days before menstruation is also possible unintended pregnancy, it is recommended that the patient under the guidance of a doctor to take safer contraceptive measures.