Your baby’s development

My baby is 4 months old: when should I ask?

Every baby has their own pace, and comparing them with the neighbour’s child rarely helps. Even so, there are a few things most babies already do by around 4 months. When one of them doesn’t appear, it is worth mentioning.

Asking doesn’t mean something is wrong. It means looking in time. In these first months your baby’s nervous system changes enormously, and the sooner we support them, the easier it is to help.


What a 4-month-old usually does

It isn’t a test. These are things at least 3 in 4 babies do at this age, according to the milestones of the CDC and the American Academy of Pediatrics.

Head and body

Holds their head steady when you carry them. Lying on their tummy, they lean on their forearms and lift their head to look.

Hands

Keeps their hands open most of the time, brings them to their mouth and holds a toy if you put it in their hand.

Eyes and hearing

Follows you with their eyes and turns their head towards your voice.

Connection

Smiles to get your attention, makes sounds and “answers” when you talk to them.


If at 4 months your baby still…, ask about it

  1. Doesn’t hold their head up when you pick them up

    Or their head lags behind when you pull them up to sitting by the hands.

    Illustration: an adult pulls a baby lying on their back up by the hand, and the baby’s head lags behind.
    Illustration: a baby held face down on one hand under the tummy; the head, arms and legs hang down.
    Illustrative images.
  2. Keeps their hands closed almost all the time

    Or the thumb tucked inside the fist, and it is hard to open them.

    A baby’s closed hand, with the thumb tucked inside the fist.
    A baby’s closed fist.
    Illustrative images.
  3. Clearly uses one side more than the other

    One hand, one arm, or always turns their head to the same side.

  4. Doesn’t follow you with their eyes

    Or doesn’t react to sounds or to your voice.

  5. Doesn’t smile when you smile at them

    Or seems very passive to you, as if “switched off”.

  6. Startles hugely at any noise

    Or is irritable almost all day.

A single one of these signs is not a diagnosis. It is a reason for someone with experience to take a calm look.


At any age

If they stop doing something they already did, ask soon

Don’t wait for the next check-up.

Faster isn’t always better

Sometimes a baby with more muscle tension than usual does things early, always towards the same side or in an odd order. For example, they roll from back to tummy long before they can roll back. If you see something like that, mention it.

Leave reflexes to your paediatrician or your physio

There is no need to test them at home. What you can notice is that, month by month, your baby moves from automatic movements to movements with intention: looking, searching, reaching.

Your intuition counts

No one knows your baby like you do. If something worries you, ask.


If your baby was born premature

Count their corrected age: the months since the date they were due. A baby born two months early who is 4 months old is assessed as a 2-month-old. This correction is usually applied during the first 18 to 24 months.


Looking early is caring

Most of the time, a consultation ends with an “all is well” and a few tips for home. And when something more is needed, having seen it early makes the difference.

If you have doubts about how your baby moves, write to me and we will look at it together.

Sources

  • Zubler J et al. Evidence-Informed Milestones for Developmental Surveillance Tools. Pediatrics, 2022. https://doi.org/10.1542/peds.2021-052138
  • Noritz GH, Murphy NA (AAP). Motor Delays: Early Identification and Evaluation. Pediatrics, 2013. https://doi.org/10.1542/peds.2013-1056
  • Desarrollo neurológico normal del niño. Pediatría Integral (SEPEAP), 2015.
  • AEPap. Desarrollo psicomotor y signos de alarma, 2016.
  • Signos de alerta en el desarrollo psicomotor. Vox Paediatrica (SPAOYEX).
  • Hospital Sant Joan de Déu y CAPSBE. Document de consens sobre alteracions del desenvolupament psicomotor, 2008.
  • OMS. Guidelines on Physical Activity, Sedentary Behaviour and Sleep for Children under 5, 2019.
  • Tabla de desarrollo Haizea-Llevant.
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