Note: All weights and lengths are approximate; each baby is unique. These figures are just general ranges.
Communication and social development
At three months, baby becomes interested in what’s going on in her greater environment. When she’s laid on her tummy, she’ll lift her head high for a longer stretch of time (which is harder than it may sound, because her head is relatively very heavy at this point and her muscular system is still quite weak). She may babble in a singsong way. She’ll express happiness when you’re giving her attention, chatting with her or even just sitting nearby.
Senses and motor skills
Baby's hands are mostly open now. At this age, physical contact is very important. Caressing, massaging, stroking her cheeks and playing with her arms and legs foster development.
Interests and activities
If a rattle or toy is placed in the hand of a three-month-old, she can firmly grasp it and look at it — but not see it in complete detail. She’s soaking in information about her surroundings by observing them extensively.