Normally, not breastfeeding overnight during breastfeeding does not cause regained milk. During breastfeeding, breastmilk will slowly become more abundant through the child’s sucking, and if the child does not suckle, it will indeed lead to regained milk. Generally speaking, not breastfeeding for a day or a night will not cause regained milk, but only after two or three days or more. If you don’t breastfeed for a long period of time, your breasts may become swollen and painful, and you must use a breast pump to suck out the milk, which will encourage the mammary glands to continue to secrete milk. If the milk keeps rising and you don’t care about it, it will easily cause blockage of the milk ducts, and in serious cases, it will lead to mastitis, which will then affect your child’s daily suckling. If any discomfort occurs during breastfeeding, you should go to the hospital for examination in time so as not to affect yourself and your child.