Are you an expecting or newborn parent and have questions about COVID-19? Click here.

An in depth explanation of a baby's key milestones

Heather Morris, a Registered General Nurse and a State Certified Midwife of over 25 years, provides a detailed introduction of milestones, and the importance of recognising them during a child's development.


Much is written and discussed about baby ‘milestones’ and most parents/care givers are likely to check their baby’s development using some form of milestone markers.

This series is designed for health professionals to show at a glance the generally recognised milestones, how these fit in with guidelines for visits, assessments and vaccinations, together with some advice at each stage which may be useful to discuss with parents. Potential ‘red flag’ warning signs are also included for each milestone.

Developmental milestones are acquired in a sequential order and they can be considered in four areas of skill sets:

  • Gross motor
  • Vision and fine motor
  • Hearing, speech and language
  • Social, emotional and behavioural

Milestones should be considered in terms of their ‘median age of acquisition’ (when half of a standard population of infants achieve that level) and the ‘limit age’ by which they should have been achieved. Limit ages are usually considered to be two standard deviations from the mean age of acquisition. If the skill is not achieved by this age, more detailed assessment, investigation or intervention may be required. For example, when considering the milestone of walking – the median age is 12 months, with a limit age of 18 months.

It’s important to recognise these milestones as they are useful guidelines to help track an infant’s development and to help identify any potential problems. Early recognition and appropriate intervention are key in managing any identified delays in development. This makes understanding these key ‘developmental milestones’ of particular value to health professionals.

Preterm infants and milestones

Most children who are born prematurely have a good developmental outcome, but when assessing a baby born preterm their ‘corrected age’ (depending on gestation) should be used.

A premature baby’s  developmental (corrected) age is calculated from their original due date (and not the date they were born). This should be used for the first two years when assessing their functional and developmental skills (such as walking and talking). [NICE, 2017]

‘Red flags’

When evaluating an infant’s developmental milestones, the following may be regarded as ‘red flag’ situations, which couldrequire further investigation:

  • Strong parental concerns about the child
  • Significant loss of skills
  • Lack of response to sound or visual stimuli
  • Poor interaction with adults or other children
  • Lack of, or limited eye contact
  • Differences between right and left sides of the body in terms of strength, movement or tone
  • Marked low tone (floppy) or high tone (stiff and tense) which significantly impacts on development and functional motor skills

General tips for assessing development

  • Consider the child’s age (corrected age if born prematurely) and focus discussions with the parents on the likely areas of current developmental progress.
  • Offer the child suitable toys to assess skills through play.
  • Observe how the child uses toys and interacts with people.


References Accessed 4th September 2019

Red Flags early identification guide – birth to five years, Childrens Health Queensland hospital


Read about a baby's first milestones

Metanium Nappy Rash Ointment is a medicine. Always read the label.