The heavy menstrual flow is generally normal. If the menstrual period is simply heavy and lasts for about 3-7 days, it usually has little effect on the body and is a normal reaction, but if the menstrual period is heavy and lasts for a longer period of time, you need to consult a doctor in time. The main reasons for heavy menstrual flow after menstruation are as follows: 1. Changes in hormone levels in the body: After giving birth, due to changes in hormone levels in the body, estrogen stimulates excessive thickening of the uterine lining, which can lead to an increase in the amount of menstruation when it falls off. 2. Abnormal ovarian function: due to postnatal breastfeeding ovarian function is unstable, secretion level is also abnormal, the endometrium is affected by hormone levels, excessive thickening of the endometrium may occur and produce excessive menstrual flow or amenorrhea and other situations, such as stopping breastfeeding, ovarian function will return to normal, so that the amount of menstruation to return to normal. Therefore, if the menstrual flow is not relieved, you need to consult a doctor in time.