Your baby at week 4: 1-month milestone — what to expect

At week 4, 1-month milestone. Sleep pattern: first real smile. Feeding: sleep stretches lengthen. Special note: more alert windows.

What week 4 typically looks like

At 1-month milestone, most babies show first real smile and sleep stretches lengthen. More alert windows. Wermom data from 50,000+ tracked babies confirms this range — though every baby is on their own timeline.

Sleep patterns this week

Typical wake windows at week 4 run 60-120 minutes depending on baby's individual rhythm. Total 24-hour sleep target: 14-17 hours. Track wake windows in your sleep app to identify your baby's specific pattern.

Feeding rhythms

At week 4, expect sleep stretches lengthen. Watch for early hunger cues: rooting, hand-to-mouth, soft fussing. Late cues (crying) mean you missed the window. Logging cue + time pattern over 7 days reveals your baby's rhythm.

Milestone watch

This week: 1-month milestone. AAP guidelines specify a range, not a date. Babies on either end of normal are still normal. Document what your baby does — for your reassurance and for your pediatrician check-in.

Red flags worth a pediatrician call

Sudden total sleep drop (<11h sustained 5+ days). Refusing feeds for 24+ hours combined with fewer wet diapers. Significant loss of previously-shown skills. When in doubt, the AAP recommends call. Worst case: you confirm everything's fine.