Do you know the early signs of autism?

While many children with autism spectrum disorders (ASDs) don't show signs until well into toddlerhood, there's good evidence some clues may be observable even before their first birthday. Other symptoms will likely appear by the time they turn 2 years old.

Though these behaviors may not necessarily point to autism, being aware of them can help parents and guardians get early diagnosis and treatment—crucial to a child's overall development and function.

The first signs

An absence of social back-and-forth is one of the early signs of autism in babies. In their first year, if a baby isn't smiling, making eye contact or attempting to communicate through expressions and sounds, it may signal an issue.

“As early as 9 months—this is the earliest visit where I’ll pick up on things, such as not responding to their own name and poor eye contact,” says Sierra Coartney, DO, a pediatrician at LewisGale Physicians in Salem, Virginia. “It's increasingly concerning if a child has still not acquired these skills by 12 months,” she adds.

At 1 year, children should have begun to communicate using hand gestures, like waving or reaching for things. Babbling—making noises that may imitate grown-up speech patterns—is also typical by this age. A lack of either could be a sign of autism in a 1 year old. "If they're not babbling by 9 months or saying one or two words by 1 year, then their speech is considered delayed," says Dr. Coartney. "Speech delay coupled with poor social skills especially raises concern for autism."

At this stage, if you call your child's name and there's no reaction, it could be a cause for concern, as well. Don't be alarmed if they don't respond to an unfamiliar face, though. Coartney says not acknowledging someone new, like a recently hired babysitter, isn't necessarily a sign of developmental delay.

Another possible clue, however: poor joint attention skills. When an 8- or 10-month-old baby discovers something appealing, they'll frequently use gestures to try to catch your eye and share what they've found. They'll often look at you to make sure you're paying attention, too, and follow your gazes and gestures. These are social interactions children with ASD don't show much interest in—and their absence is considered a hallmark of the condition, especially by the second year.

Clues after the first year

Between the ages of 12 and 24 months, previous early signs of autism, like a lack of interaction, may become more pronounced, and other new clues might surface. These could include:

• No verbal development—no words at 16 months, and no simple phrases that convey meaning at 24 months
• Strange body or hand movements, like rocking, hand flapping or excessive clapping
• Babbling that sounds like whining or humming
• An unusual fixation with a particular object, like a toy
• Losing a gained ability, like language

"Tantrums that are out of proportion, [perhaps] in response to a change in routine, an overwhelming environment or sounds that do not bother other children, such as background noise in a restaurant," are another sign, says Coartney. A child not getting their way is a more typical cause for a meltdown, she adds.

Plans for treatment

It's important to note: While these early behaviors may point to autism, they could indicate a different health issue. "A speech delay can be a sign of autism or a range of medical conditions, such as a hearing problem," says Coartney. "It may be an isolated finding that still needs addressed, though it's not associated with any other development problems." They may also mean nothing at all—and simply be part of your child's development.

In addition to looking for early signs of autism at all well baby visits, the American Academy of Pediatrics recommends pediatricians screen for ASD as part of well visits at 18 and 24 months. Many use a test called the M-CHAT, a 20-point questionnaire followed by an interview. "A child is evaluated for language and communication, social skills, motor skills and for any atypical behaviors seen in ASD," says Coartney. It may also be useful for detecting developmental delays in general.

However, you can—and should—reach out to your child's pediatrician at any time if you're concerned about the potential for ASD. They can perform a screening, and if signs point toward a possible problem, recommend a formal evaluation. Pediatricians should also screen for conditions that often occur with autism, including speech and feeding delays, as well as gastrointestinal problems. Autism can be diagnosed reliably by age 2, though most cases aren’t identified until age 4, according to the Centers for Disease Control and Prevention—often because adults don't recognize the clues.

An early diagnosis of autism means earlier intervention—the most effective way of improving outcomes for a child. "Early intervention is a system of services available in every state for children under 3 to address development delays, including in areas of speech and communication, fine and gross motor skills, cognitive skills, social skills and emotional skills," says Coartney.

Pediatricians should refer children for intervention at the first indication of a problem, even if it’s before age 2. Every state provides resources and at least some funding for the services; speak to your healthcare provider or get in touch with your state's Part C coordinator for more information.