The 4-month sleep regression is common as sleep cycles mature.
rolls front to back; babbles; reaches for and grabs toys.
Milestones are ranges, not deadlines. Healthy babies reach them weeks apart.
Every baby is different. These are typical ranges for healthy, full-term babies, not targets. The easiest way to know your baby's normal is to track a couple of weeks and look at the pattern.
Thungu is a baby-tracking bot, not medical advice. If you're worried about feeding, weight, sleep, or development, talk to your pediatrician.