If ovarian function is normal and the uterus has recovered, an unbreastfeeding mother will have her period about 6-8 weeks after delivery, while the time for breastfeeding mothers to resume menstruation varies. With the improvement of people’s living standard, maternal nutrition is generally richer, and the uterus recovers faster, it is not abnormal for an unbreastfeeding mother to resume menstruation at 42 days after delivery. During lactation, a large amount of lactogen will be produced in the body, which will inhibit the female endocrine system, so that the ovaries will be inhibited for a long time, and there will be no ovulation, and the secretion of estrogen will be very low, which will be manifested as amenorrhea. Generally speaking, menstruation can be resumed about 6 months after delivery with the gradual recovery of ovarian function. In addition, some mothers may not resume menstruation during the entire breastfeeding period, and only after the end of the breastfeeding period does estrogen gradually return to normal levels and menstruation occurs, which is normal.