Autism Risks Related to Pregnancy and Birth

How to Reduce the Risk of Autism

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A higher chance of having a child on the autism spectrum is associated with several pregnancy-related issues. Some of these, such as the use of certain pharmaceuticals during pregnancy, can be managed to reduce the risk. Others, however, are difficult, if not impossible, to change.

It’s important to remember that an association is not the same thing as a cause. For example, it's a fact that preterm babies are more likely to have autism than full-term babies, but it's not known exactly why. The reasons may actually relate more to genetics or to socioeconomic factors than to the behaviors of the birth parent.

This article will discuss the pregnancy-related factors associated with autism, including which are supported by the most evidence, which have weaker associations, and what you can do to reduce the risk.

Established Pregnancy-Related Factors

Multiple well-researched, large studies have found a link between certain pregnancy-related factors and autism, and the results have been reproduced in later studies. These factors, therefore, are valid, though they raise the risk of autism only slightly. If it’s possible for you to minimize these risks, your likelihood of having a child with autism will be reduced.

Reducing Risk of Autism During Pregnancy and Birth

Verywell / Michela Buttignol

Antiepileptic Drugs

Some common antiepileptic drugs, particularly valproate (sold under the brand names Depakene and Depakote), have been shown to increase the risk of autism when taken by the childbearing parent during pregnancy. Valproate, in particular, may raise the risk by as much as 10%.

If you are considering pregnancy, talk with your neurologist about changing or even stopping your medication to reduce the risk of autism.

Older Parents

Quite a few large studies suggest that older parents are significantly more likely to have children with autism. There is some evidence to suggest that this phenomenon is more likely when the male genetic parent is older, though there is some evidence that the age of the childbearing parent is a factor, as well.

It may be helpful to discuss this issue with a doctor if it relates to your situation.

Preterm Birth

A number of studies have found a correlation between preterm birth and autism, as well as other developmental disorders. About 7% of children born preterm have autism, compared with 1%–2% of children in the general population.

A related risk is low birth weight. While there is no way to completely eliminate the risk of early delivery, it is possible to lower that risk. Speak with your doctor if you are at increased risk of delivering early.

Gestational Diabetes

A large study finds that if the birth parent experiences gestational diabetes (diabetes first diagnosed when pregnant) there is a greater-than-average likelihood of having a child with autism. Any form of diabetes mellitus in the birth parent can be a risk factor. Gestational diabetes can’t always be avoided, but it can be carefully managed with the support of a doctor.

Possible Pregnancy-Related Risk Factors

Some risk factors have been researched by well-established individuals under appropriate circumstances, but the findings have not been reproduced enough times to be conclusive. If you have concerns, you’re better off avoiding these possible risks, though it’s not absolutely certain that they will increase your risk of having a child on the autism spectrum.

Taking Tylenol (Acetaminophen) During Pregnancy

Use of Tylenol during pregnancy is very common as it is one of the only pain relievers considered safe during pregnancy. However, there is a growing concern that it may be linked to increased risks for the child, including for neurodevelopmental disorders such as autism and attention deficit hyperactivity disorder (ADHD).

Birth cohort studies in Spain and Denmark found an association between Tylenol use during pregnancy and autism in the child. One smaller study of the umbilical cord blood of children who were later diagnosed with autism or ADHD found that those with more acetaminophen in their pre-birth blood supply were more likely to develop the disorders.

The American College of Obstetricians and Gynecologists (ACOG) does not recommend any changes in how physicians prescribe acetaminophen at this time until more definitive research is done.

Environmental Toxins

Exposure to certain environmental toxins, such as PBDEs (polybrominated diphenyl ethers), PCDDs (polychlorinated dibenzodioxins), PCBs (polychlorinated biphenyls), and BPA (bisphenol A) may increase the risk of autism. While earlier studies found a connection, more recent studies were inconclusive. These are toxins found in certain plastic goods, newly built houses, new carpets, and even some food packaging.

Meta-Analysis Findings

Rather than doing their own unique studies, some researchers take the time to analyze multiple studies on related topics. This allows them to find commonalities among multiple studies and to discover trends and uncover surprises.

These large reviews of studies are called meta-analyses, and several such meta-analyses have looked at research into autism and pregnancy. According to these reviews, the following pregnancy-related issues are associated with autism in more than one study:

  • Autoimmune disease in the birth parent 
  • Infections during pregnancy 
  • Prenatal stress

A single, older meta-analysis uncovered a much longer list of possible pregnancy issues associated with increased risk of autism, including abnormal presentation of the fetus, umbilical cord complications, fetal distress, birth injury or trauma, multiple births, maternal hemorrhage,   
low birth weight, small for gestational age, congenital malformation, and feeding difficulties.

While this list is long, it’s important to remember that many of these issues may appear in a single pregnancy and birth, and are usually associated with premature birth. For example, prenatal stress, congenital malformation, and other issues may lead to an early birth, which is associated with low birth weight.

Premature infants often have issues with feeding. A baby who has low birth weight but is born at full-term and has no other issues may have only a tiny statistically increased risk of autism.

Reducing Risk of Autism During Pregnancy and Birth

Based on the research, there are several steps a birth parent can take to reduce the risk that their child will have autism. They include:

  • Having children after the age of 21 and before the age of 35 and choosing a male genetic parent in the same age range
  • Working with a doctor to choose safer medications for specific issues, such as epilepsy
  • Avoiding activities such as smoking or being around known toxins
  • Making regular prenatal visits to the doctor and following up on any potential physical issues, such as emerging gestational diabetes   
  • Closely following any medical advice regarding bed rest and stress avoidance

According to studies, your baby may also benefit from consistent and appropriate use of specific supplements. Taking supplements such as folate (folic acid), omega-3s, and vitamin D3, correcting vitamin deficiencies, boosting your immune system, and prolonging breastfeeding are all mentioned in research findings as possible ways to reduce the risk of autism (though, of course, they can't eliminate the risk altogether).


Determining pregnancy-related risk factors for autism is an ongoing area of research. Some risk factors have more evidence of an association than others. Taking certain antiepileptic drugs, being older parents, having a preterm birth, and developing gestational diabetes are believed to be risk factors. Possible risk factors include environmental toxins and taking Tylenol during pregnancy.

A Word From Verywell

Every pregnancy is unique, and it is impossible to avoid all potential risks to your baby. Simple measures can, however, decrease risks for many conditions.

At the same time, it’s important to remember that autism is known to have a strong connection to genetics. If you or your partner has autism or you have family members on the spectrum, your risk of having a child with autism increases no matter how carefully you manage your pregnancy.

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By Lisa Jo Rudy
Lisa Jo Rudy, MDiv, is a writer, advocate, author, and consultant specializing in the field of autism.