The best time to lose belly after childbirth is after the puerperium, that is, 42 days after delivery. In the 42 days after childbirth belongs to the puerperium, this time to rest, need to avoid strain, strenuous exercise. During the puerperium, the whole body organs and systems of the mother will return to their normal state before pregnancy as soon as possible, such as uterine rejuvenation and recovery of reproductive organs. But it should be noted that during this period the pelvis will still be congested, not conducive to slimming exercise. And 42 days after giving birth to the uterus has been completely lowered to the pelvis, pelvic floor tissue, fascia ligament, uterine ligaments and wound sites have basically returned to the non-pregnant state, can be normal slimming exercise. It is recommended that pregnant women take aerobic exercise to slim their bellies after childbirth, such as swimming, jogging, yoga, etc.