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Wait until your child is ready. Buy a waterproof mattress cover. Keep spare linens and pajamas close at hand. Maintain a relaxed attitude.
Your child may have mastered staying dry during the day, but that does not mean that he or she will be ready to stay dry at night. For most children, it's fine to keep them in diapers (or pull-up style disposable underwear) until they start waking up dry most mornings. Understand that developmentally, each child is different. Some children can stay dry at night during the toddler years; others are still having accidents at age six or beyond. Try not to compare your son or daughter to other children. Once you decide to give up nighttime diapers, you'll want to prepare for the inevitable accidents. Get a waterproof cover to put under the sheets but above the mattress, to protect it from damage. When your child has an accident in the middle of the night, it's helpful to have clean sheets and pajamas nearby. That way, you can simply remove the soiled sheets, wipe the waterproof cover with a cloth, put clean sheets on the bed, and help your child change into fresh sleepwear. As your child gets older, you may want to enlist his or her help in this routine. Most preschoolers can remove soiled sheets, put on clean pajamas, and help you put clean linens on the bed. Accidents will happen and, indeed, they may happen very frequently at first and it's important that you support your child and take them in stride. Tell your child that learning to stay dry at night is a process and that it's okay if it takes some time.