Month six

There's no 5-month checklist, so this month sits between two of them (Zubler et al., 2022). The one ahead is the 6-month list. By then, most babies know familiar people, like to look at themselves in a mirror, and laugh; take turns making sounds with you, blow raspberries, and squeal; put things in their mouth to explore them, reach for a toy they want, and close their lips to show they don't want more food; and roll from tummy to back, push up on straight arms on their tummy, and lean on their hands to hold themselves up when sitting (CDC). Those lists describe what at least 75% of babies do by each age, so a missing skill is a reason to check in, not to wait and see (Zubler et al., 2022). If your baby was born early, count by corrected age until age 2 (AAP).

The month's themes, in the order they tend to arrive. Rolling: rocking on the tummy, kicking, and "swimming" with the arms are the warm-up, and many babies roll both ways by about 7 months, usually tummy to back first (AAP). Sounds: giggles, raspberries, and vowels sometimes joined to a consonant, like "aaaagoo" or "daaaa" (ASHA). Teeth: the first usually appear between 6 and 10 months, though discomfort can start weeks or months earlier (AAP). And food: the AAP recommends only breast milk for about the first 6 months (AAP), so this month is for getting ready, not starting. All of it is in the 5-month guide.

Tummy time still earns its place. A systematic review of 16 mostly observational studies linked it to better gross motor development, including rolling (Hewitt et al., 2020), the AAP recommends it awake every day (AAP), and the WHO suggests at least 30 minutes a day, spread out, for babies who aren't crawling yet (WHO). The difference now is that your baby can do something with it.