It is normal for a three-month-old baby to sleep 15 to 18 hours a day. Babies sleep for a long time after birth, and as the baby grows older, the sleep time will become shorter and the waking time during the day will become longer. For three-month-old babies, it is normal to sleep about 15 to 18 hours a day, and each baby has certain individual differences. Each baby’s sleep time, sleep pattern is different, but overall sleep time is very long, but need to pay attention to observe the baby’s mental state after waking up and the baby’s development, if there is no discomfort, the baby’s state is good, good development, indicating that the baby’s sleep time is still relatively sufficient. On the contrary, it is necessary to go to the hospital in time.