Popularised by the 'Wonder Weeks', leaps line up loosely with new abilities like focusing, rolling or babbling. The science on a fixed calendar is debated, but the pattern — unsettled spell, then a new skill — is familiar to many parents. Extra closeness and patience usually carry you through.
Glossary
Developmental leap
A developmental leap is a burst of brain development that can briefly make a baby fussier, clingier and less settled as they work on a new skill.
Related guides
The 4-month sleep change
Around four months your baby's sleep grows up — more wakings now are usually a sign of healthy brain development, not a step backwards.
Milestones: 4–6 months
Between 4 and 6 months your baby starts rolling, reaching, babbling and sitting with a little help — and every baby gets there on their own timeline.
Try the tool: Baby Milestone Timeline
Related terms
General information, not medical advice. For concerns about your child, talk with your doctor or child-health nurse.