Scientists have simply demystified a major myth on autism

For years, studies have suggested that the health of a mother during pregnancy could influence her child’s probability of developing autism. However, a new revolutionary study, taking advantage of the vast medical records of Denmark, reveals another story.

The researchers found that almost all the preliminary maternal conditions previously did not really cause autism but were rather linked by genetics or environmental factors. The only associations consistent with autism came from fetal complications, which, according to scientists, are the first signs of autism rather than its cause.

Rethink the risk factors for autism

Many studies have suggested a link between the health of a mother during pregnancy and the risk of autism of her child. However, a new study reveals that almost all these connections can be explained by other factors, such as genetics, environmental exhibitions such as pollution and access to health care.

Directed by researchers from Nyu Langone Health, the study revealed that the only conditions related to pregnancy really associated with autism were complications affecting the fetus. This suggests that these complications may not be causes of autism but rather early signs.

No evidence that maternal health causes autism

“Our study shows that there is no convincing evidence that one of these other diagnoses in the mother can provoke autism,” said the main author of the study, Magdalena Janecka, Phd, Associate Professor In the Department of Children’s Psychiatry and Adolescents and the Department of Health Population, at NYU Grossman School of Medicine.

Publication in the journal Nature Medicine Online on January 31, the new study included a analysis of
The medical history of more than 1.1 million pregnancies (among 600,000 mothers) of a national register in Denmark. Unlike medical records in the United States, which are often dispersed among many different medical suppliers, a person sees in his lifetime, in Denmark more than 1,700 distinct diagnoses as defined by international standards, called ICD-10 codes . From these, the researchers concentrated their analysis on those diagnosed in at least 0.1% of pregnancies (236 diagnostics).

“We think that our study is the first to examine in depth all the mother’s medical history and to explore a wide range of possible associations, by controlling several simultaneous conditions and confusion factors,” said the Main author of the Vahe Khachadourian, MD, PHD, MPH study, an assistant research teacher at the Department of Children and Psychiatry Adolescent at the NYU Grossman School of Medicine.

Denmark has set up strict guarantees to avoid misuse of register data, explains Janecka, as it contains personal information. However, due to information specific to the individual, researchers have been able to overlap all the diagnoses of a woman with the risk of autism of her children.

Diskeel the genetic and environmental puzzle

For the study, the researchers corrected factors that could confuse or offer an alternative explanation for the link between the diagnosis that a woman has received and the diagnosis of the autism of a child. These factors include socio -demographic status and mother’s age during pregnancy, as children of older mothers are more likely to be diagnosed with autism, and their mothers are also more likely to receive certain diagnoses, such as hypertension, than their younger counterparts.

After taking these confusion factors into account, as well as simultaneous diagnoses, 30 were still statistically associated with autism in children. To determine if they occurred alongside rather than provoking autism, the researchers then included the brothers and sisters of autistic children in the analysis. If a mother was diagnosed with the same condition during pregnancies of children affected and without autism, this suggests that factors other than her diagnosis influenced the link with autism. This step has untangled the conditions that could be attributable to family factors, such as genetics and environmental exposure to pollution, from those who can cause autism.

The role of genetics in the risk of autism

According to researchers, genetics is a strong family confusing (plausible explanation) of autism. Some of the same genes related to depression are also associated with autism. If a mother suffers from depression during pregnancy and her child is diagnosed later with autism, this is more likely due to shared genetic factors rather than depression itself affecting the fetus during development.

Researchers also analyzed the medical history of fathers. Any association between a paternal diagnosis and autism would most likely be caused by family factors, because the father’s direct effects on a post-design fetus are probably very limited. In fact, researchers have observed that many paternal diagnoses are just as linked to children’s autism as maternal diagnoses.

Fetal complications: early signs, no cause

After taking into account the family factors, the only maternal diagnosis which was still strongly associated statistically with autism was the complications of pregnancy linked to the fetus.

“Our interpretation is that these fetal diagnoses probably do not cause autism, but are rather early signs,” said Janecka. “The predominant hypothesis is that autism really starts prenatually. Even before a child received a diagnosis for autism, development changes took place all the time.

Move the story of parents

“Many mothers of autistic children feel guilty,” said Janecka, “thinking he did something wrong during pregnancy, and it’s heartbreaking. I think that showing that these things will not cause autism are important and can lead to more effective means of supporting autistic children and their families. »»

Autism is a development disorder that generally emerges in childhood, affecting social interactions and behavior. Symptoms may vary considerably and may include reduced visual contact, difficulty engaging in the game, repetitive movements or a word and unusual responses to sensory experiences such as temperature. Although these traits can persist in adulthood, they differ from person to person. According to federal estimates, autism affects approximately 1 in 54 children in the United States.

Reference: “Most associations between maternal health and autism are attributable to family confusion” January 31, 2025, Nature Medicine.
DOI: 10.1038 / S41591-024-03479-5

Financial support for the study was provided by

“Data-Gt-translate-attrattes =” ({“attribute =” “tabindex =” 0 “role =” link “> National Institutes of Health Subsidies R01MH124817 and T32MH122394, the Lundbeck Grants Foundation R102-A9118 and R155-201424, the Seaver Foundation and the Eunice Kennedy Shriver National Institute of Child Health and Human Development Grant HD09888.

Other co-researchers of the study are Elias Speeman ARILERSKOV, Jakob Grove and Stefan Nygaard Hansen in

“Data-gt-translate-attrattes =” ({“attribute =” “tabindex =” 0 “role =” link “> Aarhus university in Denmark; Paul O’Reilly, Joseph Buxbaum, Abraham Reichenberg and Sven Sandin at the Icahn School of Medicine in Mont Sinai in New York; Lisa Croen at Kaiser Permanent Nord-California in Oakland; And Diana Schendel at Drexel University in Philadelphia.