Have you ever worried that a single thing you did without thinking could harm the one you love most? Welcome to pregnant life! With a mom’s gestational health under scrutiny as an explanation for Autism Spectrum Disorder, it’s no surprise then that it’s a source of unease. But what if a mom’s choices aren’t to blame for autism? A team of NYU scientists and doctors say that when it comes to autism, nature has a far stronger effect than prenatal nurture. So what’s the link between autism and mom’s health?
Autism now affects one in 36 children, a number that continues to grow as awareness and diagnostics improve. This is the latest, according to CDC’s Autism and Developmental Disabilities Monitoring Network in 2020, encompassing children aged 8 years diagnosed with autistic spectrum disorder from health records and educational service providers in the United States. 1 For mothers, this diagnosis has long come with guilt, fear, and the relentless question: What did I do wrong? A new study published in Nature Medicine this year may shift that narrative.
Nature vs nurture
For Jamie McCleary, Executive Director at Autism Canada, and a mother of three children with autism, the findings of this new study feel like long overdue validation.
Jamie was diagnosed with autism after her children at the age of 41. She has spent years navigating a complex emotional terrain. The difficulties come not just in supporting her kids through their diagnoses, but in confronting the societal tendency to blame mothers for autism.
‘When you have one child with autism, you are likely to have another. And even many parents end up diagnosed themselves,’ she says. ‘So for the focus to be on blaming moms for so long, that’s just ridiculous to me.’
Autism researchers at NYU’s Langone Health medical centre have similar thoughts. In a landmark study, investigators have asked a bold question, what if a mother’s choices during pregnancy are not to blame for autism? In a huge observational study, the New York-based team probed the relationship between a kid’s autism spectrum diagnosis and their mom’s health and medical care through pregnancy.
‘We believe our study is the first to comprehensively examine the entire medical history of the mother and explore a wide range of possible associations, controlling for multiple concurrent conditions and confounding factors,’ says Dr. Vahe Khachadourian, lead author of the study and Research Assistant Professor, Department of Child and Adolescent Psychiatry at N. Y. U. Grossman School of Medicine in a press release by NYU2.
Navigating a confusing world
A person with autism has a neurodevelopmental disorder that affects how they communicate, interact and experience the world. The condition often includes social communication challenges, and some form of restrictive or repetitive behaviour. Researchers believe autistic traits to arise from structural and connectivity differences in the anatomy of the brain.
In 2024, Researchers at the University of Rochester discovered an abnormal number of brain cells in the brain’s grey matter in autistic children. 4 In the same year, researchers at Yale University found that autistic brains have fewer synapses – the crucial junctions that nerve cells use to send signals. 3 These anatomical and cell biology findings add weight to the idea that autism is profoundly grounded in neurodevelopment. In practice this means it’s time to reset our baseline understanding of the origins of autistic spectrum disorder. Autism seems more likely to be linked to differences in underlying brain architecture and neuronal function rather than psychological abnormalities.
Autism spectrum disorder is a lifelong condition, and for many, it can make it difficult to move through the world without assistance. Many children with autism spectrum disorder likely will need some sort of external support to help manage their disability. 5
A voyage to understanding
So if Autism spectrum disorder is a neurodevelopmental condition, you might be wondering why it seems to be everywhere these days, what changed?
Some people have interpreted the apparent increasing numbers of autism spectrum diagnoses as a sign that there is something in the environment that is causing more children to develop the condition. This, McCleary explained, is a misunderstanding.
‘It’s not an epidemic. People just know what they’re looking for now,’ she said. ‘All we’re doing is diagnosing people who’ve gone undiagnosed for the past 150 years. So it was there all along, we just didn’t look.’
Parents noticing these behaviours (sometimes the teacher) have their child assessed by a paediatrician or a paediatric psychologist. The doctor or psychologist will make a detailed evaluation and perform specialized testing to reach a diagnosis. Depending on the outcomes of the assessment, they will recommend that the child should go on to receive aid. Support for autistic children might include if deemed social skills training, speech and language therapy, and/or special education services. 5 Research into autism screening in 2021 suggests that signs of autism spectrum disorder can be detected as early as 15 months old.
Blame Games
Historically, when children have been diagnosed with Autism, parents, especially moms, have carried the weight of public and medical speculation. For example, the so-called refrigerator mother theory wrongly suggested that cold or emotionally distant parenting caused autism.
Since then, blame has shifted from parenting style to pregnancy: medication use, diet, stress and illness have all been put under the microscope. Given that the health of the mother during gestation has largely been thought a factor, researchers have been actively exploring pregnancy exposures to find a link to the condition. 6
Diabetes in pregnancy, cardiometabolic disorders and depression have been shown to correlate with higher occurrence of autism.7, 8, 9 Just last year, the New England Journal of Medicine published a study on the use of seizure medication, particularly topiramate during pregnancy leading to an increase in incidence of children born with autism. 10 These studies have raised questions as to whether exposure to medications in utero are contributing to autism rates. But were these relationships truly causal? Researchers have yet to figure out the root cause of the condition, let alone whether there exists a cause and effect relationship between mom’s medicine and an autism diagnosis.
Moms under the microscope
Pregnant women face strict limitations on what they can safely eat, take or do. Expectant mothers are advised to scrutinize everything from the ingredients of beauty products, to supplements, and so much more, and if they don’t, people around them certainly will.
For ethical reasons, it’s very difficult to investigate what is and isn’t safe during pregnancy so ‘better safe than sorry’ has been the rule. When research is limited in the area, there is not much we can deem ‘safe’. Moms-to-be have few options when it comes to medications and safety recommendations are frequently in flux. It’s not surprising that the lack of clearance consistent information about safety breeds mistrust and fear.
Can we prevent autism?
Jamie McCleary points out that expectant mothers are bombarded with messaging that their health or choices during pregnancy could lead to long-term health issues like diabetes, obesity and cardiovascular disease in their unborn child.
‘You’ve got people saying I started my son on a gluten-free diet, and his autism went away,’ she sighs. ‘That’s just not the reality of autism. It’s not something that can be fixed or repaired, it is what it is, and, it’s the identity of a person.’
‘Everyone is trying to inject you with as much fear as humanly possible,’ McCleary says. ‘It’s just right from the beginning. There is so much that people throw at you that isn’t necessarily true.’
It goes without saying that the mental load of a pregnant woman is heavy. Finally, research has delivered some information that takes some pressure off expectant mothers.
‘Your child is genetically designed to be who they are,’ McCleary says. ‘It’s no different than having blue eyes or brown eyes. People with autism aren’t broken.’
For many mothers this may come as a relief if perhaps autism has touched their families, this is one less thing to carry. This sentiment is echoed by the researchers involved in the project.
‘Many mothers of children with autism feel guilty about it,’ said Dr. Janecka, one of the study’s authors told NYU’s communications office, ‘thinking that they did something wrong during pregnancy, and it is heartbreaking. I think showing that these things are not going to cause autism is important and may lead to more effective ways to support autistic children and their families.’
So how did they show it?
What’s the link between autism and mom’s health?
In Khachadourian, Janecka and their colleagues completed a mammoth survey of 1,131,889 babies born between 1998 and 2015. The scientists collected information from health records of Danish infants from hospitalization and outpatient clinic visits. They compared the data found on the health of the mom, father and siblings. The team searched for any and all factors or events that could link a mothers’ health, a fathers’ health, or genetic and environmental influence to autism diagnosis in the babies.
They initially identified maternal health conditions that appeared to be associated with autism in their children. Next the scholars dug deeper, probing the health of the autistic baby’s sibling. They used something called discordant sibling analysis. This method allowed them to compare siblings where one kid has autism and the other does not, to see if both were exposed to the same maternal health issues during pregnancy. If exposure was the same but outcomes were different, the cause is likely not the maternal condition, but rather shared genetic or environmental factors. Using paternal negative controls, they also looked at the health of the father to understand whether there were any connections to the autism in the children. This would further compound the theory of genetics having influence on the development of autism in the youngster, as the fathers’ health at the time of the pregnancy would not affect the fetus.
Revelations and reevaluations
The results? Of the 1,131,899 children born to 648,901 mothers, 18,374 kids received an autism diagnosis during the study. Thirty maternal diagnoses were found to be associated with the child developing autism.
These included mental health conditions, obesity, and metabolic disease, to name a few. Of the total children with autism in the sample, 12,138 were from families where one sibling had autism, and one sibling did not. Using discordant sibling analysis, they were able to show that the association between maternal health conditions and autism dropped by 38% for non-chronic and 71% for chronic conditions overall and then 51% and 71% when focusing in on the specific comparisons that already got weaker. They were then able to show a subtle lowering in the data showing maternal link to autism by investigating the paternal health data. Further weakening the association of maternal health during pregnancy being linked to autism.
Overall they discovered that when you look for an association between an event, for example a broken knee or a few doses of an anti-seizure drug, and autism, you might see the traces of a correlation. Sometimes it’s a real but small relationship, other times it could be a statistical blip. These associations, however, are dwarfed by the influence of the mother and father’s genes.
What’s more, Swedish researchers have previously found that some of the associations between prenatal use of some medicines and autism are more likely to be indirect relationships. 11 This means that it’s more plausible that a woman has an underlying neurological problem with her brain that causes symptoms that need the medication. It’s the inherited aspect of their neurodevelopment that influences their child’s chances of developing autism spectrum disorder not the drugs.
This study marks a milestone on the journey to dispel harmful myths about autism and to find better ways to approach the condition. The researchers at N.Y.U. Langone Health are helping rewrite the story, gifting some certainty to our expecting mothers, and taking some of the burden off moms whose family has perhaps been touched by the disorder.
People with autism aren’t broken
When asked what would she would say to expectant mothers who worry that something they did during pregnancy caused their child’s autism, Jamie McCleary is gentle but clear:
‘That’s just not how it works. If your child is genetically designed to be who they are there’s no changing that genetic design,’ she says.
‘People with autism aren’t broken,’ McCleary continued, ‘We don’t need to be fixed. We just see the world in a different way, maybe more colourfully, maybe louder. That’s not something to fear. There’s no limits on what that child can do regardless of their diagnosis.’
References
- Maenner MJ, Warren Z, Williams AR, et al. Prevalence and Characteristics of Autism Spectrum Disorder Among Children Aged 8 Years – Autism and Developmental Disabilities Monitoring Network, 11 Sites, United States, 2020. MMWR Surveill Summ 2023;72 (No. SS-2):1–14. DOI: http://dx.doi.org/10.15585/mmwr.ss7202a1
- No Evidence That Maternal Sickness During Pregnancy Causes Autism. NYU Langone News. Accessed April 23, 2025. https://nyulangone.org/news/no-evidence-maternal-sickness-during-pregnancy-causes-autism
- Matuskey D, Yang Y, Naganawa M, et al. 11 C-UCB-J PET imaging is consistent with lower synaptic density in autistic adults. Mol Psychiatry. 2025;30(4):1610–1616. doi:10.1038/s41380-024-02776-2
- Christensen ZP, Freedman EG, Foxe JJ. Autism is associated with in vivo changes in gray matter neurite architecture. Autism Research. 2024;17(11):2261–2277. doi:10.1002/aur.3239
- What Is Autism Spectrum Disorder? Accessed April 23, 2025. https://www.psychiatry.org:443/patients-families/autism/what-is-autism-spectrum-disorder
- Khachadourian, V., Arildskov, E.S., Grove, J. et al. Familial confounding in the associations between maternal health and autism. Nat Med 31, 996–1007 (2025). https://doi.org/10.1038/s41591-024-03479-5, https://www.nature.com/articles/s41591-024-03479-5
- Ornoy A, Becker M, Weinstein-Fudim L, Ergaz Z. Diabetes during Pregnancy: A Maternal Disease Complicating the Course of Pregnancy with Long-Term Deleterious Effects on the Offspring. A Clinical Review. Int J Mol Sci. 2021;22(6):2965. doi:10.3390/ijms22062965
- Lyall K, Ning X, Aschner JL, et al. Cardiometabolic Pregnancy Complications in Association With Autism-Related Traits as Measured by the Social Responsiveness Scale in ECHO. Am J Epidemiol. 2022;191 (8):1407–1419. doi:10.1093/aje/kwac061
- Hagberg KW, Robijn AL, Jick S. Maternal depression and antidepressant use during pregnancy and the risk of autism spectrum disorder in offspring. Clin Epidemiol. 2018;10:1599-1612. doi:10.2147/CLEP.S180618
- Hernández-DÃaz S, Straub L, Bateman BT, et al. Risk of Autism after Prenatal Topiramate, Valproate, or Lamotrigine Exposure. N Engl J Med. 2024;390 (12):1069–1079. doi:10.1056/NEJMoa2309359. https://www.nejm.org/doi/full/10.1056/NEJMoa2309359
- Ahlqvist VH, Sjöqvist H, Dalman C, et al. Acetaminophen Use During Pregnancy and Children’s Risk of Autism, ADHD, and Intellectual Disability. JAMA. 2024;331 (14):1205–1214. doi:10.1001/jama.2024.3172
Disclosure: Quotes from Jamie McCleary were taken from a recorded interview and have been lightly edited for clarity and flow. Thank you to Jamie for her generosity with her time and her helpful advice.
Have you ever worried that a single thing you did without thinking could harm the one you love most? Welcome to pregnant life! With a mom’s gestational health under scrutiny as an explanation for Autism Spectrum Disorder, it’s no surprise then that it’s a source of unease. But what if a mom’s choices aren’t to blame for autism? A team of NYU scientists and doctors say that when it comes to autism, nature has a far stronger effect than prenatal nurture. So what’s the link between autism and mom’s health? Autism now affects one in 36 children, a number that continues to grow as awareness and diagnostics improve. This is the latest, according to CDC’s Autism and Developmental Disabilities Monitoring Network in 2020, encompassing children aged 8 years diagnosed with autistic spectrum disorder from health records and educational service providers in the United States. 1 For mothers, this diagnosis has long come with guilt, fear, and the relentless question: What did I do wrong? A new study published in Nature Medicine this year may shift that narrative. For Jamie McCleary, Executive Director at Autism Canada, and a mother of three children with autism, the findings of this new study feel like long overdue validation. Jamie was diagnosed with autism after her children at the age of 41. She has spent years navigating a complex emotional terrain. The difficulties come not just in supporting her kids through their diagnoses, but in confronting the societal tendency to blame mothers for autism. ‘When you have one child with autism, you are likely to have another. And even many parents end up diagnosed themselves,’ she says. ‘So for the focus to be on blaming moms for so long, that’s just ridiculous to me.’ Autism researchers at NYU’s Langone Health medical centre have similar thoughts. In a landmark study, investigators have asked a bold question, what if a mother’s choices during pregnancy are not to blame for autism? In a huge observational study, the New York-based team probed the relationship between a kid’s autism spectrum diagnosis and their mom’s health and medical care through pregnancy. ‘We believe our study is the first to comprehensively examine the entire medical history of the mother and explore a wide range of possible associations, controlling for multiple concurrent conditions and confounding factors,’ says Dr. Vahe Khachadourian, lead author of the study and Research Assistant Professor, Department of Child and Adolescent Psychiatry at N. Y. U. Grossman School of Medicine in a press release by NYU2. A person with autism has a neurodevelopmental disorder that affects how they communicate, interact and experience the world. The condition often includes social communication challenges, and some form of restrictive or repetitive behaviour. Researchers believe autistic traits to arise from structural and connectivity differences in the anatomy of the brain. In 2024, Researchers at the University of Rochester discovered an abnormal number of brain cells in the brain’s grey matter in autistic children. 4 In the same year, researchers at Yale University found that autistic brains have fewer synapses – the crucial junctions that nerve cells use to send signals. 3 These anatomical and cell biology findings add weight to the idea that autism is profoundly grounded in neurodevelopment. In practice this means it’s time to reset our baseline understanding of the origins of autistic spectrum disorder. Autism seems more likely to be linked to differences in underlying brain architecture and neuronal function rather than psychological abnormalities. Autism spectrum disorder is a lifelong condition, and for many, it can make it difficult to move through the world without assistance. Many children with autism spectrum disorder likely will need some sort of external support to help manage their disability. 5 So if Autism spectrum disorder is a neurodevelopmental condition, you might be wondering why it seems to be everywhere these days, what changed? Some people have interpreted the apparent increasing numbers of autism spectrum diagnoses as a sign that there is something in the environment that is causing more children to develop the condition. This, McCleary explained, is a misunderstanding. ‘It’s not an epidemic. People just know what they’re looking for now,’ she said. ‘All we’re doing is diagnosing people who’ve gone undiagnosed for the past 150 years. So it was there all along, we just didn’t look.’ Parents noticing these behaviours (sometimes the teacher) have their child assessed by a paediatrician or a paediatric psychologist. The doctor or psychologist will make a detailed evaluation and perform specialized testing to reach a diagnosis. Depending on the outcomes of the assessment, they will recommend that the child should go on to receive aid. Support for autistic children might include if deemed social skills training, speech and language therapy, and/or special education services. 5 Research into autism screening in 2021 suggests that signs of autism spectrum disorder can be detected as early as 15 months old. Historically, when children have been diagnosed with Autism, parents, especially moms, have carried the weight of public and medical speculation. For example, the so-called refrigerator mother theory wrongly suggested that cold or emotionally distant parenting caused autism. Since then, blame has shifted from parenting style to pregnancy: medication use, diet, stress and illness have all been put under the microscope. Given that the health of the mother during gestation has largely been thought a factor, researchers have been actively exploring pregnancy exposures to find a link to the condition. 6 Diabetes in pregnancy, cardiometabolic disorders and depression have been shown to correlate with higher occurrence of autism.7, 8, 9 Just last year, the New England Journal of Medicine published a study on the use of seizure medication, particularly topiramate during pregnancy leading to an increase in incidence of children born with autism. 10 These studies have raised questions as to whether exposure to medications in utero are contributing to autism rates. But were these relationships truly causal? Researchers have yet to figure out the root cause of the condition, let alone whether there exists a cause and effect relationship between mom’s medicine and an autism diagnosis. Pregnant women face strict limitations on what they can safely eat, take or do. Expectant mothers are advised to scrutinize everything from the ingredients of beauty products, to supplements, and so much more, and if they don’t, people around them certainly will. For ethical reasons, it’s very difficult to investigate what is and isn’t safe during pregnancy so ‘better safe than sorry’ has been the rule. When research is limited in the area, there is not much we can deem ‘safe’. Moms-to-be have few options when it comes to medications and safety recommendations are frequently in flux. It’s not surprising that the lack of clearance consistent information about safety breeds mistrust and fear. Jamie McCleary points out that expectant mothers are bombarded with messaging that their health or choices during pregnancy could lead to long-term health issues like diabetes, obesity and cardiovascular disease in their unborn child. ‘You’ve got people saying I started my son on a gluten-free diet, and his autism went away,’ she sighs. ‘That’s just not the reality of autism. It’s not something that can be fixed or repaired, it is what it is, and, it’s the identity of a person.’ ‘Everyone is trying to inject you with as much fear as humanly possible,’ McCleary says. ‘It’s just right from the beginning. There is so much that people throw at you that isn’t necessarily true.’ It goes without saying that the mental load of a pregnant woman is heavy. Finally, research has delivered some information that takes some pressure off expectant mothers. ‘Your child is genetically designed to be who they are,’ McCleary says. ‘It’s no different than having blue eyes or brown eyes. People with autism aren’t broken.’ For many mothers this may come as a relief if perhaps autism has touched their families, this is one less thing to carry. This sentiment is echoed by the researchers involved in the project. ‘Many mothers of children with autism feel guilty about it,’ said Dr. Janecka, one of the study’s authors told NYU’s communications office, ‘thinking that they did something wrong during pregnancy, and it is heartbreaking. I think showing that these things are not going to cause autism is important and may lead to more effective ways to support autistic children and their families.’ So how did they show it? In Khachadourian, Janecka and their colleagues completed a mammoth survey of 1,131,889 babies born between 1998 and 2015. The scientists collected information from health records of Danish infants from hospitalization and outpatient clinic visits. They compared the data found on the health of the mom, father and siblings. The team searched for any and all factors or events that could link a mothers’ health, a fathers’ health, or genetic and environmental influence to autism diagnosis in the babies. They initially identified maternal health conditions that appeared to be associated with autism in their children. Next the scholars dug deeper, probing the health of the autistic baby’s sibling. They used something called discordant sibling analysis. This method allowed them to compare siblings where one kid has autism and the other does not, to see if both were exposed to the same maternal health issues during pregnancy. If exposure was the same but outcomes were different, the cause is likely not the maternal condition, but rather shared genetic or environmental factors. Using paternal negative controls, they also looked at the health of the father to understand whether there were any connections to the autism in the children. This would further compound the theory of genetics having influence on the development of autism in the youngster, as the fathers’ health at the time of the pregnancy would not affect the fetus. The results? Of the 1,131,899 children born to 648,901 mothers, 18,374 kids received an autism diagnosis during the study. Thirty maternal diagnoses were found to be associated with the child developing autism. These included mental health conditions, obesity, and metabolic disease, to name a few. Of the total children with autism in the sample, 12,138 were from families where one sibling had autism, and one sibling did not. Using discordant sibling analysis, they were able to show that the association between maternal health conditions and autism dropped by 38% for non-chronic and 71% for chronic conditions overall and then 51% and 71% when focusing in on the specific comparisons that already got weaker. They were then able to show a subtle lowering in the data showing maternal link to autism by investigating the paternal health data. Further weakening the association of maternal health during pregnancy being linked to autism. Overall they discovered that when you look for an association between an event, for example a broken knee or a few doses of an anti-seizure drug, and autism, you might see the traces of a correlation. Sometimes it’s a real but small relationship, other times it could be a statistical blip. These associations, however, are dwarfed by the influence of the mother and father’s genes. What’s more, Swedish researchers have previously found that some of the associations between prenatal use of some medicines and autism are more likely to be indirect relationships. 11 This means that it’s more plausible that a woman has an underlying neurological problem with her brain that causes symptoms that need the medication. It’s the inherited aspect of their neurodevelopment that influences their child’s chances of developing autism spectrum disorder not the drugs. This study marks a milestone on the journey to dispel harmful myths about autism and to find better ways to approach the condition. The researchers at N.Y.U. Langone Health are helping rewrite the story, gifting some certainty to our expecting mothers, and taking some of the burden off moms whose family has perhaps been touched by the disorder. When asked what would she would say to expectant mothers who worry that something they did during pregnancy caused their child’s autism, Jamie McCleary is gentle but clear: ‘That’s just not how it works. If your child is genetically designed to be who they are there’s no changing that genetic design,’ she says. ‘People with autism aren’t broken,’ McCleary continued, ‘We don’t need to be fixed. We just see the world in a different way, maybe more colourfully, maybe louder. That’s not something to fear. There’s no limits on what that child can do regardless of their diagnosis.’ Disclosure: Quotes from Jamie McCleary were taken from a recorded interview and have been lightly edited for clarity and flow. Thank you to Jamie for her generosity with her time and her helpful advice.
Nature vs nurture
Navigating a confusing world
A voyage to understanding
Blame Games
Moms under the microscope
Can we prevent autism?
What’s the link between autism and mom’s health?
Revelations and reevaluations
People with autism aren’t broken
References
