Delayed menstruation and heavy menstrual flow for a few days may be caused by biochemical pregnancy or spontaneous abortion, endocrine disorders, uterine diseases, taking hormone drugs and so on. Delayed menstruation with heavy menstrual blood is firstly considered to be related to pregnancy, such as biochemical pregnancy or spontaneous abortion, etc. It is recommended to take blood HCG test in time. Delayed menstruation and heavy menstrual bleeding may be caused by endocrine disorders, such as stress, emotional tension, sadness, etc.; it may also be caused by uterine diseases, such as endometritis, uterine fibroids, endometriosis, etc.; the use of hormonal medications, such as the Emergency Contraceptive Pill (ECP), etc., may also cause delayed menstruation and increased menstrual bleeding. During menstruation, you should maintain a good mood and mentality, avoid catching cold, and if you have uterine diseases, you should treat the primary disease in time and pay attention to vulvar hygiene to avoid infection caused by upward movement of bacteria.