The first day of menstruation came a little bit and then no more, this bleeding is not necessarily menstruation, during the period if you have sex, not good contraception, to rule out the abnormal bleeding caused by accidental pregnancy, generally more than 12 days after intercourse can be measured with a test strip, or directly to the hospital to take a blood test of blood HCG, which can be ruled out the gold standard of pregnancy. In addition, if you take emergency contraceptive pills within this menstrual cycle, it may also lead to menstrual disorders, or even delayed menstruation. After ruling out pregnancy, you should come to the hospital for an ultrasound to see the thickness of the uterine lining. If the uterine lining is thicker than 8mm, you can take progesterone to induce menstruation. If you take progesterone for 5 days, 200mg per day, and after taking it, you don’t have your period, you can wait for another 10 days, and if you don’t have your period for 10 days, you must come to the hospital.