When Will My Baby Roll Over and Sit Up?

There are lots of reasons behind the popularity of 5K road races. We love the idea of making progress and hope to improve our finishing times. And as much as we might hate to admit it, we like comparing our times to those of others our own age.

It makes sense, then, that when it comes to babies, we delight at watching them achieve their motor milestones—seeing them assume new positions and move new ways. We share in their accomplishments as they sit, stand, and walk. And even though there are no medals given out, we like to know that our little ones are comparing favorably to their peers of the same age.

This “baby watching” habit is very much as it should be, and not just from a proud parent perspective. Knowing whether your baby is on track, more or less, with others his age is important for his overall developmental health. Not only are motor delays a reason to seek out some “catch-up” intervention; they also can be signs of a more concerning condition.

With this in mind, let’s look at what we know about two of the most prominent baby motor milestones: rolling over, and sitting up. But first, we shall talk about some general considerations about how babies progress in getting moving.

Some (Getting Off the) Ground Rules

As a rule, motor development in infants progresses from head to toe. The first major gross motor (large muscle) milestone we generally look for is the lifting of the head off a surface on which the baby is lying prone (face down). Next, we see the chest come with the head, and so on, all the way down to increased use of the legs. Walking, in many ways, is the culmination of this progression, although, of course, motor development continues to progress beyond this milestone.

A second caveat is that children progress at different rates; there is a wide variety of normal. If an “average age” that a child does Activity X is quoted, that means roughly half of all children perform that activity later. We frequently are called upon to explain this when we talk about “growth percentiles,” and the same logic applies to development. In other words, if there aren’t a lot of concerning signs, providers will allow quite a bit of leeway in saying what’s normal.

Finally, milestones are not always achieved in the same order, and occasionally, a milestone can be skipped altogether in a normal child. For example, I’ve seen more than a few children who did a lot of things on time, movement-wise, but no one ever saw them roll over.

Speaking of Rolling (and, For That Matter, Sitting)

OK, then: when should she be rolling? By 3 months of age, infants are generally rolling to their side. By 4 months, they roll from front to back. At 5 months of age, they usually also roll from back to front. Interestingly, this sequence has begun to change lately: with the advent of “back to sleep,” sometimes back-to-front rolling comes first, probably because babies don’t experience being on their stomachs as much.

The next major motor milestone to which we pay a lot of attention is sitting. Generally, a 6-month old will sit with support (either with his back against something and/or leaning on his hands). One month later, he’ll sit without any support, and at 8 months, babies are generally able to move on their own from lying to sitting.

When to Be Concerned

We’ve talked a little bit about the variability in child development and about a couple of important milestones. Yet, these two are only part of the big picture.

Most pediatricians would be concerned if there’s no sitting by 9 months of age. While rolling seems a little more variable, if there isn’t at least some effort by 6 months of age, that might be a reason for concern. Pediatric providers screen for problems in development at every physical during the first few years, both by asking questions and during the examination. (If the baby were seeing me, for example, you might not notice it as part of the exam, because I might at the same time be prattling on about immunizations, or solid foods, or even about the next 5K! But we’re all looking for things like the ability to keep the head up and the overall muscle tone.) Most pediatricians are also screening using a more formal questionnaire once a year for the first couple of years.

More formal screening is usually needed if a parent or another caregiver (such as a daycare provider) has a concern about development, unless it’s truly known to be a normal variant. And a provider may choose to refer on if there are major concerns suspected. Where motor delays are concerned, a pediatric neurologist might be the specialist of choice, and, as with other delays, the local early intervention specialists are also likely to be involved.

Homework for Parents

If an infant or young child has a motor delay, it seldom has anything to do with what the parents have done or not done. But it’s always good to pass on some things to think about.

First off, do some things to encourage movement from an early age. A bright mobile above the crib will get him reaching. A plastic mirror will get him turning his head. “Tummy time” (when awake only!) will give him the incentive to begin lifting his head.

Second, avoid the use of devices like baby walkers. Although we’re most concerned about safety, there’s some thinking that they may impede motor development.

Third, always notify your provider if your baby is not progressing as quickly as you think she should. And remember that you can access early intervention services free of charge. This doesn’t require a referral from your provider, and they can do testing as well as provide therapy. Do all you can to ensure her movement’s on track now, and before you know it, she’ll be out there running her first 5K!

Stan Sack
Dr. Stan Sack has 29 years’ experience as a primary care pediatrician in Massachusetts and Florida. A medical writer since 2015, he enjoys blogging on topics that are on parents’ minds but are covered less often in books and on websites. He lives in the Florida Keys with his family and enjoys healthy cooking, fitness activities and singing in his spare time.

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