Why has my baby suddenly become sleepy all the time?

A sudden increase in sleepiness in infants may be related to multiple factors: 1. Diseases or infections are common causes. When babies are ill, such as having a cold, flu, or other infections, they may exhibit excessive sleepiness. Fever or physical discomfort may require babies to rest more in order to help restore energy and immune function. 2. Changes in the living environment or diet may also affect the baby's sleep patterns. For example, new environments, changes in dietary composition, or alterations in daily routines may lead to increased sleep duration. If there have been recent environmental or dietary changes, it may be necessary to observe whether these factors are related to the baby's excessive sleepiness. 3. Developmental stage transitions may also lead to increased sleepiness in babies. Infants and young children may sometimes experience brief changes in sleep patterns during different growth stages, which could be a normal phenomenon during development. If the baby's excessive sleepiness is accompanied by other abnormal symptoms such as persistent fever, decreased appetite, or lethargy, prompt medical attention is recommended.