Babies often notice major changes in their sleep habits after 3-4 months. Just as your baby leaves a newborn and his sleep patterns become more predictable – bam – you can see big changes. Sudden awakenings during the night, short sleep, anxiety or sleep disturbances? Yes – maybe the 4 month sleep regression is to blame.
What is 4-Month Sleep Regression?
When babies are around 3-4 months old, their sleep patterns begin to mature. Instead of continuing to sleep as newborns, their models now have additional cycles of light sleep and deep sleep.
It is important to note that sleep changes at this stage are due to biological changes in the child's sleep habits, not regressions caused by temporary conditions. Simply put, your baby may wake up more often because they are growing and developing, not because they are coming back.
Developmental changes from 3-4 months
At this age, babies begin to produce melatonin, which regulates our sleep-wake cycle. As long as newborn sleep isn't tightly controlled by circadian rhythms, things begin to change at this age. Sleep begins to mature, and babies begin to sleep in phases and cycles, similar to adults.
Once the baby begins to sleep deeply, there will be a brief wake-up period after each cycle. While this waking phase can lead to new sleep problems, it's actually a pretty cool innate defense mechanism and allows the body to check the environment to make sure everything is safe and sound all night.