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Sarah Biren
Sarah Biren
March 27, 2024 ·  5 min read

Study Shows C-Sections Linked to Autism and ADHD: What does it mean?

This article was originally published on September 5, 2019, and has since been updated.


A Swedish study has sparked some debate. The 2019 study claimed that babies born through a Caesarean section are more likely to be autistic and develop ADHD. The research published in the journal JAMA Network Open analyzed over 20 million children, and its results showed that there was a 33% and 17%  higher chance of children developing autism and ADHD, respectively. [1]

The scientists behind the study are not claiming a causal relationship between c-sections and autism or ADHD, however other scientists and health professionals fear the outcome of public perception following media coverage. This is because they argue that Caesarean delivery merely correlates with the disorders, and the exact cause is a deeper, more complex issue.

In fact, some state it’s more likely that autism is a result of the same factors that cause C-sections to be needed. They insist that the procedure is not a direct cause of autism and that parents should not be afraid of undergoing the procedure. [2] The purpose of the study is preliminary, and the key meaning of it is to try and understand the possible mechanisms behind the associations, which is particularly important given the increase in c-sections for non-medical reasons [1]

The Statistics of Caesarean Births

In 1990 approximately 6% of all births were done via c-section, as of 2018 this has more than tripled according to a study published in The Lancet [3]

The operation surgically removes the baby by cutting across the abdomen, instead of the usual vaginal delivery. It is used in cases where the health of the mother or the baby is at stake, for cultural reasons, or if the mother is afraid of giving birth naturally.

Studies have found that c-section deliveries are linked childhood obesity [4], or develop allergies [5], asthma [6], type one diabetes [7], and leukemia [8]. However, connecting C-sections to psychiatric disorders has incomplete evidence according to the team from the Karolinska Institutet in Sweden. [1]

Medical Reasons for a Caesarean [9]:

  • Complications with previous births/miscarriages
  • Complications arising during labor or vaginal birth
  • The baby is in a breech position (where the head is not facing down as it should)
  • Baby is sideways or keeps changing positions
  • Mother has a low-lying placenta
  • Mother has medical conditions like heart disease or diabetes
  • Expecting twins or more
  • Baby is not developing enough in the womb
  • The mother has eclampsia or severe pre-eclampsia, and cannot delay the birth 

The Study in Detail

The meta analysis was led by PhD student Tianyang Zhang. The team analyzed 61 studies which involved the details of 20,607,935 births in 19 countries. leading them to the correlation between Caesarean births and neurodevelopmental disorders.

“These results remained the same whether the C-section had been done for medical reasons or chosen by the mother,” the researchers said.

Autism and ADHD are not very well-understood conditions, but genetics are believed to be a large factor. They are neurodevelopmental disorders, which means they each have notable differences in behavioral development. In autism, the differences affect the brain connected to social and communication development. For ADHD, it affects the ability to direct and control attention. [10]

The researchers reference the findings of other studies that look to explain the correlation of c-section births and negative outcomes. One theory is that the child is never exposed to the bacteria in the vaginal canal nor experiences the natural stress response that occurs during a natural birth. These two missing elements may affect the brain’s development. [1]

However, this does not convince other experts.

Kings College London’s Professor Andrew Shannan said,

“The need for Caesarean is often caused by problems that could influence brain function, such as a poorly functioning placenta. It is highly unlikely the caesarean delivery itself is causal in these mental health conditions, from our current understanding of brain physiology and the effects of caesarean.”

“Women should not be alarmed by the need for a Caesarean which is often performed to reduce risk to their baby.”

Richard Kennedy, medical director at Birmingham and Solihull Local Maternity System added, “Women should be reassured that Caesarean section carried out in the UK is a very safe operation. Performed for appropriate clinical reasons it can be life saving for the mother and baby. Any association with pediatric outcomes is more likely to relate to underlying maternal conditions rather than the Caesarean itself.” [11]

However, Zhang’s team argues that a link between C-sections and brain damage could help reduce the rates of unnecessary procedures, Despite being a life-saving procedure in the presence of complications, no evidence, to our knowledge, indicates that cesarean delivery, if not indicated [medically mandatory], is beneficial for the offspring.” [1]

They explain that cases where a Caesarean birth is chosen because of culture, previous negative experiences, or general fear, may indicate a genetic susceptibility to factors such as stress that correlates with neurodevelopmental or psychiatric conditions in children. [1]

Because of the risks of the children developing illnesses like diabetes and leukemia associated with C-section babies, the researchers hope their findings might reduce cases where the procedure is not necessary. However, they emphasized that their study does not claim that C-sections cause these disorders, and surgical delivery can be lifesaving and should be used whenever needed. [2] 

The team went on to investigate whether C-sections can be linked to learning disabilities, OCD, and eating disorders, but no links were found.

Dr. James Findon, psychology lecturer at King’s College, summed up that it’s important to remember that the study does not state that C-sections causes these disorders, as this has been disproved by sibling studies. What it does show is a possibility that the genetic or environmental factors that create a need for a Caesarean birth may also cause neurodevelopmental disorders.

For example, this procedure is often recommended to mothers with diabetes, hypertension, obese, older, a history of immune conditions, and so on. These diseases can affect the child’s brain development in the womb. [10]

“Parents should be reassured that Caesareans are a largely safe procedure when medically indicated,” Findon concluded. [11]

Sources

  1. Tianyang Zhang. Association of Cesarean Delivery With Risk of Neurodevelopmental and Psychiatric Disorders in the Offspring https://jamanetwork.com/journals/jamanetworkopen/fullarticle/2749054 August 28, 2019
  2. Gene Emery. Possible link between C-section and autism, ADHD https://www.reuters.com/article/us-health-csection-brain/possible-link-between-c-section-and-autism-adhd-idUSKCN1VI1VS August 28, 2019
  3. Optimizing caesarean section use https://www.thelancet.com/series/caesarean-section
  4. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6181954/
  5. https://www.jacionline.org/article/S0091-6749(18)31070-4/fulltext
  6. https://onlinelibrary.wiley.com/doi/abs/10.1111/j.1365-2222.2007.02780.x
  7. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3237660/
  8. https://www.sciencedaily.com/releases/2016/02/160227110702.htm
  9. Tefo Mokate.What are the reasons for having a caesarean section? https://www.babycentre.co.uk/x1029502/what-are-the-reasons-for-having-a-caesarean-section June 2016
  10. https://theconversation.com/theres-no-evidence-caesarean-sections-cause-autism-or-adhd-122473[11] Science Media Center. Expert reaction to study on caesareans and neurodevelopmental disorders https://www.sciencemediacentre.org/expert-reaction-to-study-on-caesareans-and-neurodevelopmental-disorders/ August 28, 2019