The Adventure: Infant Development 4 to 6 Months

The other day a friend of mine mentioned how right when babies start to get into a routine and really interact…we have to go back to work! Ugh! The three month mark is tough in terms of that if you’re a working mom, but no matter what the fourth, fifth and sixth month are an exciting time for you and your baby. She really starts to experience the world instead of just observing it. For her that’s such an adventure, and for you it is quite entertaining!

In terms of lying on her back (supine), she will gradually lift her legs up. This is the most basic, foundational element of all movement. We’re hoping she doesn’t have a diastasis and that her spine is flat (so her head isn’t tilted back).

The cover of Marianne Hermsen-Van Wanrooy's book, "Baby Moves," provides
an excellent example of the supine position for babies four to six months in age.

She’ll learn to grasp objects at midline and then across her body. She will also start to grasp her feet—you know that cute position where they can start to stick their toes in their mouths. But this is more than cute, it’s also an indication that she can lift her pelvis off the surface and stabilize on the upper part of her back (Marianne Hermsen-Van Wanrooy, p. 35).

With motivation and this ability to stabilize, she will learn to roll to each side. As her mommy, you should make sure she is rolling to each side. Our son preferred rolling to the left, so we ended up blocking his left side with an ottoman and put more motivation on the right—toys and ourselves. Pretty soon he was able to go both directions just fine.

Eventually, this rolling to each side will become a complete roll over, with baby supporting herself on her elbow. As a mommy, you should...write this date down in her baby book!

Thanks to all of her hard work (and yours), she is also mastering tummy time. She is able to see the world from a new perspective, which really provides motivation for additional movements. She will begin to use one of her hands to grasp for toys, so she’ll learn to support her weight on one elbow. 

During these months, we’re also looking for her to rotate her head, eyes and tongue without her body as this indicates that there has been integration of locomotion function. By the fifth month we’re looking for baby to support herself on the proximal parts of her palms and her thighs. (Dynamic Neuromuscular Stabilization, seminar notes.)

Do’s and Don’ts

• Do offer your baby small, light objects that she can easy lift and that are safe for her to put in her mouth (because everything will be going in her mouth!). Hermsen-Van Wanrooy suggests simple things like a sock (p. 37).
• Do off the objects to one hand at a time (p. 37).
• Do place toys on the floor to the side of your baby (p. 37).
• Don’t use toys that hang above her as these can cause muscle imbalance (p. 37).
• Don’t sit or stand your baby up (p. 48). I know it’s tempting, but she isn’t quite ready for that yet. We’re getting closer though!