Common drugs taken by millions of Americans during pregnancy may increase a child’s risk of autism, a landmark study suggests.
As autism now affects one in 31 American children – a stark increase from one in 150 in the early 2000s – experts are searching for potential causes, ranging from better diagnostic criteria to pollution and medications.
Now, researchers in Nebraska have honed in on prescription medications that block the production of cholesterol.
Along with statins, these drugs – known collectively as sterol biosynthesis-inhibiting medications (SBIMs) – also include common antidepressants and beta blockers, used to treat anxiety and high blood pressure.
While cholesterol can build up in the arteries and lead to heart disease, it’s also crucial for forming protective brain cell membranes and synaptic functioning, which helps neurons communicate.
In the study of more than six million maternal-child health records, the team found that these drugs’ ability to disrupt cholesterol pathways was linked to a 1.5-fold increased risk of a child developing autism.
And for each additional SBIM prescribed, the risk increased an additional 1.3 times. Women who took four or more SBIMs ended up more than twice as likely to have a child with autism.
The study authors, from the University of Nebraska Medical Center, have urged pregnant women not to stop any of these medications abruptly without medical supervision. Instead, they encourage doctors to consider alternatives.
A new study has found taking common prescription drugs during pregnancy may increase the risk of a child being born with autism (stock image)
‘Our findings do not suggest that these medications are unsafe for adults,’ Dr Karoly Mirnics, senior study author and dean and director of the UNMC Munroe–Meyer Institute, said.
‘But they raise important questions about their use during pregnancy, a period when even small biochemical disruptions may have outsized effects on fetal brain development.
The findings come after a major Danish study found Tylenol use was not tied to a ‘significant’ risk of autism, despite claims from President Donald Trump and Department of Health and Human Services Secretary Robert F Kennedy Jr.
The new study, published in the journal Molecular Psychiatry, looked at 6.14 million maternal–child health records from the Epic Cosmos database, which represent nearly one–third of all US births between 2014 and 2023.
The team also evaluated prescriptions for 14 different SBIMs. They included the antipsychotics aripiprazole (Abilify) and haloperidol (Haldol), as well as the anxiety drug buspirone (BuSpar).
Antidepressants included were bupropion (Wellbutrin), fluoxetine (Prozac), sertraline (Zoloft) and trazodone.
The researchers also looked at beta blockers metoprolol, propranolol, nebivolol, as well as statins atorvastatin (Lipitor), pravastatin, rosuvastatin (Crestor) and simvastatin (Zocor).
Collectively, these drugs account for about 400 million yearly prescriptions in the US.
The above graph shows the comparison of autism incidence between children whose mothers used sterol biosynthesis–inhibiting medications (SBIMs) and those who did not
Of the 196,447 children diagnosed with autism, 14.2 percent had prenatal exposure to SBIMs.
Additionally, use of SBIMs increased over time, from 4.3 percent of pregnancies in 2014 to 16.8 percent in 2023.
The researchers found mothers who were prescribed at least one SBIM during pregnancy had a 1.5–fold increased chance of having an autistic child, and for each additional SBIM, the risk increased 1.3 times.
Mothers who were taking four or more SBIMs during pregnancy showed a 2.3–fold increased risk of having an autistic child.
The brain contains about 20 percent of the body’s total cholesterol, which creates synapses, or connections between neurons, along with protective membranes. Many children with autism, however, have low cholesterol, suggesting disruptions in their brains’ communication networks.
The genetic disorder Smith-Lemli-Opitz syndrome (SLOS), affecting one in 20,000 US births, has also been shown to disrupt the brain’s cholesterol–producing pathway, and 75 percent of children with this disorder also meet the criteria for autism spectrum disorder.
Stopping drugs such as antidepressants and beta blockers can lead to disastrous consequences, including withdrawal symptoms such as fever, chills, severe anxiety and heart palpitations.
Instead, the researchers urge doctors treating pregnant patients to evaluate all medications that could have sterol–inhibiting effects and look for safer alternatives.
