3-month-old babies do not sleep during the day may be related to environmental factors, too much sleep at night, diseases such as gastrointestinal dysfunction and so on. 1. Environmental factors: such as daytime sleeping environment is not good, too noisy and quiet, the room is bright, the baby lacks a sense of security and thus do not sleep during the day. 2. Too much sleep at night: if the baby sleeps too much at night, the baby usually does not sleep during the day, which is a normal phenomenon. 3. Diseases: such as gastrointestinal dysfunction, the baby may have bloating and other discomforts, it will affect the baby sleep. 3 months baby daytime sleeplessness may also have other reasons, it is recommended to go to the hospital in a timely manner, improve the examination to clarify the cause of the disease, under the guidance of the doctor’s treatment.