After a delayed period, if you have normal sex, you should first rule out the possibility of pregnancy. The method is very simple and the result can be easily obtained by checking the urine HCG. After ruling out the possibility of pregnancy, it is recommended to perform an ultrasound examination in the obstetrics and gynecology department, the main purpose of which is to observe the thickness of the lining of the uterus. If the lining of the uterus is thick, progesterone withdrawal bleeding is required, either oral preparations or intramuscular progesterone injections, which should be followed by vaginal bleeding for 3-5 days after stopping the drug. A single delayed menstrual period can be observed, but if there is repeated delayed menstruation and prolonged menstrual cycles, this falls into the category of abnormal uterine bleeding, and medication should be used to adjust the menstrual cycle.