The first thing to understand about the “4 Month Sleep Regression” is that it’s not actually a regression at all. In fact, it’s a very positive step forward and marks a major developmental milestone. As your baby’s brain matures, so does your little one’s sleep cycles, and they develop into cycles much closer to adults.
However, you might not be jumping for joy as this change often causes more frequent night waking and shorter daytime naps too. This period of change can last anywhere from a few days to six weeks.