Baby Development at 4 Months

Smiles and laughter often become easier to spot. Your baby might smile at you in a mirror, laugh at a repeated song, or grizzle instead of crying when frustrated. These small emotional shifts are part of learning that people respond, routines repeat, and feelings can be shared.

Hearing and attention are improving too. Your baby may turn toward you when you speak, respond to a familiar sound, or look around after a toy drops. Try talking from different sides, singing the same nappy-change song, reading a short board book, or using one simple rattle so your baby can practise turning and focusing.

Floor play matters more now because movement is building quickly. Give your baby supervised time on a mat, tummy time, and side-lying play instead of long stretches in bouncers, baby seats, capsules, or prams. Small bursts of free movement help neck, shoulder, back, and coordination skills.

Growth checks can be reassuring, but they are not a competition. Pregnancy Birth and Baby notes that birth weight often doubles by 4 to 6 months. Growth charts, nappies, feeding, alertness, and your baby's usual pattern matter together, so ask for advice if weight, feeds, vomiting, nappies, or energy worries you.

The 4-month immunisation visit needs calendar space. Pregnancy Birth and Baby's current Australian schedule lists 4-month vaccines including DTPa, hepatitis B, polio, Hib, rotavirus, pneumococcal, and meningococcal B for eligible children. Book early, bring the health record, and confirm the current National Immunisation Program schedule with your GP, nurse, or immunisation provider.

Outings may need fewer newborn extras and more movement planning. Pack nappies, wipes, spare clothes, feeding supplies, a burp cloth, a safe play mat or blanket, a sun-safe hat if needed, and a simple toy that can be washed. At friends' houses, check floors for pet food, cords, coins, batteries, small toys, and sharp or hot objects before putting your baby down.