The usual menstrual cycle is 28 days, menstruation delayed for 6 days, may be due to pregnancy, weekday life irregularities, but also may be caused by drug factors or ovarian function decline. 1. Pregnancy. If a woman of childbearing age has sex, delayed menstruation may be caused by pregnancy. After pregnancy, the estrogen and progesterone in the body do not retreat, and the endometrium can not be peeled off, so there will be menopause. 2. Irregular daily life. If the patient usually excessive dieting, life stress, stay up late, etc., may disturb the hypothalamus Gong brain, resulting in delayed menstruation. 3. Drug factors. Long-term oral short-acting contraceptive pills or repeated oral emergency contraceptive pills may inhibit ovarian function and cause menstrual delay. 4. Ovarian function decline. After the age of 45, due to the decline of ovarian function, women may also experience menstrual disorders, such as delayed menstruation and prolonged menstrual period. There are many reasons for delayed menstruation, so it is recommended to consult a doctor in time to find out the cause of the problem.