The first post-partum menstruation time is relatively long, a lot of cases are normal: 1, the endometrium in the estrogen and progesterone under the joint action of the shedding of menstruation will be formed. The first post-partum menstruation, due to the hypothalamus – pituitary – ovary axis of the function is not completely back to normal, the hormone secretion is not very stable can not be normal ovulation, if at this time the level of estrogen is relatively high, it will contribute to the thickening of the uterine lining, the menstrual bleeding will be a relative increase in the amount of bleeding will be relatively longer bleeding time is also relatively longer which is normal. 2, if less than a month after the birth of a vaginal bleeding symptoms, and If the bleeding is longer and heavier, it may not be caused by menstruation but by intrauterine residue. It is recommended to do ultrasound and gynecological examination in time, and if there is any residue, the uterus should be cleared in time.