For irregular menstrual bleeding, consider the following reasons: First, if a woman who has sex is of childbearing age, irregular vaginal bleeding should first be considered as a possible cause of pregnancy, so blood should be drawn for HCG. Second, excluding pregnancy, irregular vaginal bleeding in women may also be from tumors of the uterus, such as uterine fibroids, or endometrial cancer, cervical cancer, and cervical tumors, all of which can cause irregular bleeding of menstruation. Third, irregular menstrual bleeding may also be due to inflammation of the reproductive system, endometritis, uterine polyps, endometrial polyps, cervical polyps or acute cervicitis, all of which may cause irregular vaginal bleeding. Fourth, irregular menstrual bleeding may also be due to the improper use of sex hormone drugs, such as the use of emergency contraceptives, or the irregular use of other short-acting contraceptives, which can also lead to irregular vaginal bleeding. Fifth, irregular menstrual bleeding may also be caused by intrauterine foreign bodies, such as intrauterine devices that can cause irregular vaginal bleeding. Sixthly, irregular vaginal bleeding may also be due to endocrine disorders. Menstrual disorders caused by female estrogen and progesterone dysfunction can cause irregular vaginal bleeding. Irregular vaginal bleeding may also be caused by anovulatory abnormal uterine bleeding commonly seen in adolescence and menopause, or polycystic ovary syndrome and hyperprolactinemia in women of childbearing age. Seventh, it may be due to other medical conditions, such as thyroid disease or coagulation disorders, causing irregular vaginal bleeding during menstruation.