Methods of identifying the first postpartum menstrual period include observing the interval, bleeding time, bleeding volume, and the presence of normal menstrual symptoms. 1. Interval: Vaginal bleeding around 6-10 weeks postpartum in those who do not breastfeed may be the onset of menstruation. Those who are breastfeeding may not menstruate for the entire period of breastfeeding. 2. Bleeding time: The bleeding time of menstruation is usually around 5-7 days and does not occur intermittently. 3. Bleeding amount: The amount of bleeding at the first menstrual period after delivery may be more than usual, and the color is usually bright red, and then the amount and color of the bleeding will slowly decrease. 4. Whether there are normal menstrual symptoms: When you have your first menstrual period after delivery, you will usually have typical menstrual manifestations, such as pain in the chest before the onset of menstruation, emotional instability, abdominal pain, and so on. Postpartum women are advised to pay more attention to observation. If a non-nursing woman’s menstruation never comes after delivery, she can consult her doctor if necessary.