Signs of Developmental Delay in Babies: What to Look For

Quick answer: Speak to your health visitor or GP if your baby isn't smiling, making eye contact or responding to sounds by three months; isn't reaching, rolling or laughing by six months; isn't sitting, babbling or responding to their name by nine months; or isn't moving, gesturing or saying any words by twelve months. Any lost skill should be reviewed promptly.

What parents need to know

All babies develop at their own pace, and there's a wide range of what's considered normal. But knowing the signs that might indicate a developmental delay can make a real difference — because early support and intervention lead to significantly better outcomes.

This isn't a guide designed to make you anxious. It's designed to help you understand what the developmental milestones are, so you know when to seek advice with confidence.

What is a developmental delay?

A developmental delay is when a baby or child reaches milestones significantly later than expected. It can affect one area (for example, speech only) or multiple areas including motor skills, communication, social skills, and cognitive development.

A delay in one area doesn't necessarily mean there's a serious problem. But it's always worth investigating, and early referral to a specialist can make a significant difference.

Red flags by age

By 3 months

Speak to your health visitor if your baby:

• Doesn't smile in response to faces or voices
• Doesn't make eye contact
• Doesn't respond to loud sounds
• Doesn't follow a moving object with their eyes
• Has difficulty supporting their head

By 6 months

• Doesn't reach for or grasp objects
• Doesn't laugh or squeal
• Doesn't roll in either direction
• Seems very stiff or very floppy
• Doesn't show affection towards familiar caregivers

By 9 months

• Doesn't sit unsupported
• Doesn't babble ("da," "ba," "ma")
• Doesn't bear weight on legs when held upright
• Doesn't respond to their own name
• Doesn't look in the direction of pointing

By 12 months

• Doesn't crawl or attempt any form of movement
• Doesn't pull to stand
• Doesn't use gestures such as pointing or waving
• Has no words at all
• Doesn't make eye contact or engage in back-and-forth interaction

A note on regression

A skill that is lost or regressed after being established is always worth discussing with your GP or health visitor — even if other milestones are on track. Regression in social or communication skills, in particular, should be reviewed promptly.

What might cause developmental delay?

There are many possible causes, including:

• Premature birth
• Genetic conditions such as Down's syndrome
• Hearing or vision problems
• Neurodevelopmental conditions such as autism or ADHD (often identified later)
• Environmental factors
• No identifiable cause at all

A diagnosis, when made, helps unlock targeted support — it is not a label that limits your child.

Frequently asked questions

What is a developmental delay in babies?

It's when a baby reaches milestones significantly later than expected. It can affect one area, such as speech, or several areas including motor skills, communication, social skills and cognitive development.

Should I worry if my baby loses a skill they had?

A skill that is lost or regressed after being established is always worth discussing with your GP or health visitor, even if other milestones are on track. Regression in social or communication skills should be reviewed promptly.

When are NHS developmental checks done?

The NHS Healthy Child Programme includes developmental checks at 6–8 weeks, 9–12 months, and 2–2.5 years. Use them, and be honest about any concerns you have.

What causes developmental delay?

Possible causes include premature birth, genetic conditions such as Down's syndrome, hearing or vision problems, neurodevelopmental conditions such as autism or ADHD, environmental factors, or no identifiable cause at all.