What Causes Developmental Delay?

Medically reviewed by Karen Richardson Gill, MD on April 28, 2016 Written by Ann Pietrangelo

Children reach developmental milestones at their own pace. Minor, temporary delays are usually no cause for alarm, but an ongoing delay or multiple delays in reaching milestones can lead to issues later in life. Delay in reaching language,... Read More


Children reach developmental milestones at their own pace. Minor, temporary delays are usually no cause for alarm, but an ongoing delay or multiple delays in reaching milestones can lead to issues later in life. Delay in reaching language, thinking, and motor skills milestones is called developmental delay.

Developmental delay may be caused by a variety of factors, including heredity, problems with pregnancy, and premature birth. The cause is not always known. If you suspect your child has developmental delay, speak with your pediatrician. Developmental delay sometimes indicates an underlying condition that only doctors can diagnosis. Early intervention will help your child's progress and development into adulthood.

Fine and gross motor skill delay

Fine motor skills include small movements like holding a toy or using a crayon. Gross motor skills require larger movements, like jumping, climbing stairs, or throwing a ball.

Children progress at different rates, but most children can lift their head by 3 months old, sit up by 6 months, and walk well before their 2nd birthday. By age 5, most children can throw a ball overhand and ride a tricycle.

Exhibiting some of the following symptoms can mean that your child has delays in developing some fine or gross motor functions:

  • floppy or loose trunk and limbs
  • stiff arms and legs
  • limited movement in arms and legs
  • can’t sit without support by 9 months old
  • involuntary reflexes have dominance over voluntary movements
  • can’t bear weight on legs and stand up by about 1 year old

Falling outside the normal range is not always cause for concern, but if your child is unable to perform tasks within the expected time frame, speak to your doctor.

Speech and language delay

According to the National Institute on Deafness and Other Communication Disorders (NIDCD), the most active time for learning speech and language is the first three years of life, as the brain develops and matures.

The language learning process begins when an infant communicates hunger by crying. By 6 months old, most infants can recognize the sounds of basic language. At 12 to 15 months old, infants should be able to say a few simple words, even if they aren’t clear. Most toddlers can understand a few words by the time they are 18 months old. When they reach the age of 3, most children can speak in brief sentences. 

Speech and language delay are not the same. Speaking requires the muscle coordination of the vocal tract, tongue, lips, and jaw to make sounds. Speech delay is when a child stutters or has difficulty producing sounds the correct way. A disorder that makes it hard to put syllables together to form words is called apraxia of speech.

A language disorder occurs when children have difficulty understanding what other people say, and can’t express their own thoughts. Language includes speaking, gesturing, signing, and writing.

Poor hearing can cause speech and language delay, so your doctor will usually include a hearing test during diagnosis. Children with speech and language delay are often referred to a speech-language pathologist. Early intervention can be a big help.

Autism spectrum disorders

Autism spectrum disorder (ASD) is a neurodevelopmental disorder that can impair your child’s ability to communicate and interact with others. Classic autism usually includes language delay and intellectual disabilities. Symptoms are sometimes obvious early on, but may not be noticed until a child reaches 2 or 3 years of age.

Signs and symptoms of autism vary, but usually include delayed speech and language skills and difficulty communicating and interacting with others. Each child will have a unique pattern of behavior with differing levels of severity. Some symptoms include:

  • failure to respond to their name
  • resistance to cuddling or playing with others
  • lack of facial expression
  • doesn’t speak or has difficulty speaking, carrying on a conversation, or remembering words and sentences
  • performs repetitive movements
  • develops specific routines
  • coordination problems

There is currently no cure for autism but early intervention and education can help your child progress more fully.

Causes and risk factors of developmental delay

According to the Centers for Disease Control and Prevention (CDC), about 15 percent of children between the ages of 3 and 17 have one or more developmental disability. Most developmental disabilities occur before a child is born but some can occur after birth due to infection, injury, or other factors.

Causes of developmental delay can be difficult to pinpoint and a variety of things can contribute to it. Some conditions are genetic in origin, such as Down syndrome. Infection or other problems during pregnancy and childbirth, as well as premature birth, can also cause developmental delay.

Developmental delay can also be a symptom of other underlying medical conditions, including:

  • autism spectrum disorders (ASDs)
  • cerebral palsy
  • fetal alcohol spectrum disorders
  • Landau-Kleffner syndrome
  • myopathies, including muscular dystrophies
  • genetic disorders, such as Down syndrome and fragile X syndrome

If you suspect your child is developmentally delayed

Remember that children develop at different rates. However, if you think your child is developmentally delayed, talk to your doctor. If your school-age child is diagnosed with developmental delay, you may be eligible for special services. Specialized services vary according to need and location.

Check with your physician and your school district to find out what services are available. Specialized education, especially when started early, can help your child progress and achieve more in school.

Treatments for developmental delays vary according to the specific delay. Some treatments include physical therapy for help in motor skill delays, and behavioral and educational therapy for help with ASD and other delays.

In other cases, medications may be prescribed. An evaluation and diagnosis from your pediatrician is crucial to come up with a treatment plan specially designed for your child.


Many genetic and environmental factors figure into a child’s development and can cause delays in their development. Even a healthy pregnancy and proper care during and after pregnancy can lead to developmental delays in children.

Although causes of delays can be hard to pinpoint, there are many treatments and support available to manage developmental delays. Be sure to speak to your doctor if you see your child exhibiting symptoms of developmental delays.

The sooner you can diagnose a delay, the better it will be for your child’s development into adulthood.

Medically reviewed by Karen Richardson Gill, MD on April 28, 2016 Written by Ann Pietrangelo

16 possible conditions

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This feature is for informational purposes only and should not be used to diagnose. Please consult a healthcare professional if you have health concerns.

Medically reviewed by Karen Richardson Gill, MD on April 28, 2016 Written by Ann Pietrangelo