4-Month-Old Milestones: What Parents Can Expect

Babies develop at different rates, and one isolated skill does not determine whether your baby has a developmental delay. Your baby may demonstrate some 4-month milestones consistently, show others only occasionally and not yet show others. 

Instead of treating the checklist as a score, look at the whole developmental picture. Notice how your baby moves, watches, listens, communicates, plays and connects with you and other caregivers. 

Your knowledge of your baby matters. Do not dismiss a concern simply because another person tells you to wait. It is always appropriate to ask your child’s pediatrician or health care provider about something your baby is—or is not—doing. 

A premature baby may need more time to reach milestones based on the date they were born. Corrected age adjusts for the number of weeks a baby arrived before their due date. 

For example, a baby who is 16 weeks old but was born six weeks early has a corrected age of approximately 10 weeks. Their provider may recommend comparing development with the younger age. 

The CDC advises using corrected age on its checklists when a baby was born more than three weeks prematurely. Ask your baby’s health care team how long to use corrected age and how it applies to your child’s development.  

ASQ-3, or the Ages & Stages Questionnaires, Third Edition, is a structured developmental screening system. It includes a 4-month questionnaire that looks at communication, gross motor, fine motor, problem-solving and personal-social skills. 

A caregiver typically completes the questionnaire, and a professional or participating program scores and interprets it. This is different from reading a general milestone article or completing an informal checklist.  

The American Academy of Pediatrics recommends developmental surveillance at every well-child visit. Standardized screening is performed at specific ages and can also be used whenever a parent, caregiver or professional has a concern.  

Talk with your baby’s health care provider whenever you have a concern. It is especially important to share concerns if your baby: 

• Has lost a skill they previously demonstrated 
• Does not seem to respond to voices or other sounds 
• Rarely watches faces or moving objects 
• Has ongoing difficulty moving their head, arms or legs 
• Is not making sounds or engaging through looks, movements or facial expressions
• Is not showing skills across several areas of development

Bring concrete examples to the appointment. Explain what you have noticed, when you first noticed it and whether the behavior happens consistently. Tell the provider if your baby was born prematurely or has other health or developmental needs. 

If concerns remain, ask whether your baby would benefit from developmental screening or further evaluation. Families in the United States can also request an evaluation through their state or territory’s early intervention program. Eligibility and available services vary by location.  

Learn what you need to know about early intervention. 

There’s no need for your baby to catch up, because he’s not behind. Development is not a race. Babies develop at their own pace and in their own way. While development does tend to progress in a particular order—most children crawl before they walk, for example—children achieve these milestones within a relatively wide time range. Rolling is no exception.

If your doctor has assessed your son’s physical and motor skills and has found that he is progressing well, he will roll when he is ready. Children are driven to learn, grow, and develop new skills. They don’t need to be pushed to take the next step. What you can do is give your son lots of time each day to play on both his belly and his back. As babies play, they are also learning how to move their bodies in order to see and do more. Babies who are held most of the day or who spend lots of time in infant seats or carriers miss this opportunity to develop the muscle strength and coordination they need to learn to roll. Most importantly, delight in who your son is right now. There is no need to rush. He’ll be moving before you know it.

Though children’s interests and skills vary, your daughter should have some curiosity about toys now, as long as they’re age-appropriate. Most 4-month-olds are able to reach out and explore toys with their hands, and are beginning to grasp and shake or bang them. The best toys at this age are those that your daughter can easily reach and hold like rattles with handles, soft rubber rings, and toys that she can squeeze, touch, and kick. Since her toys are probably going to be sucked and gummed a lot (that’s one of the main ways babies play at this age), it’s essential that all of these objects are safe for her to put in her mouth. 

Babies this age aren’t yet able to operate toys in complicated ways, such as pressing a button on a pop-up toy. If these are the kinds of “big kid” toys that your daughter has been given, her lack of interest is understandable. She can’t easily grasp and chew on them, which is what she’s interested in right now. Instead, offer your baby a range of toys that are appropriate for her age and see how she responds. Just like most parenting challenges, choosing toys is all about trial and error. Some things you get will be a hit, while others will gather dust. (Look into starting a toy-sharing group with other moms of similarly-aged babies to make the most of your purchases.) You’ll see your daughter’s fascination with toys and other objects grow in the coming months as her hand and vision skills continue to develop. 

What’s important is that your child is showing interest in objects and people. She should be exploring the world around her by looking, by touching, and by using her mouth. She should also be using her body to communicate, such as kicking her arms and legs in delight and vocalizing back and forth with you. If you are seeing this kind of behavior and communication, then she is doing just fine. 

Your mother’s concern likely stems from the highly-publicized and very serious problem called “shaken baby syndrome.” Shaken baby syndrome results from violently shaking a baby (usually under 6 months) while holding the infant by the trunk or by the shoulders. Forceful shaking causes tearing of the small blood vessels on the surface of the brain that can interrupt blood flow and can lead to brain damage. 

The experience of being tossed up into the air no more than a foot or so is unlikely to harm your baby. This action does not generate enough force to cause your baby harm. 

However, as much as your baby enjoys being tossed into the air, there is always the chance that the person tossing her will drop her accidentally and cause physical harm. While this risk is admittedly very small, play it safe and choose other ways to be active together. Try dancing, swaying, swinging, and other movement activities that offer little or no chance of injury.