A comprehensive study involving over two million individuals has found no significant association between the use of opioid painkillers during pregnancy and the later diagnosis of autism spectrum disorder (ASD) or attention-deficit/hyperactivity disorder (ADHD). This research, conducted by scientists at Indiana University Bloomington, challenges previous studies that suggested a potential risk.
Researchers analyzed health records of more than 1.2 million children born in Sweden between 2007 and 2018. They focused on the effects of opioid use during pregnancy, specifically looking at dosage and duration on the likelihood of children developing these neurodevelopmental conditions. The study also included an additional cohort of nearly 900,000 children born from 2007 to 2015 to evaluate rates of ADHD.
The findings indicated that 2% of children born to mothers who did not use opioids received an autism diagnosis by age 10. In contrast, the rate was 2.9% for children exposed to low doses of prescribed painkillers and 3.9% for those exposed to higher doses. For ADHD, a similar trend was observed, suggesting that while there is some difference in rates, the overall evidence does not support a substantial risk increase due to opioid exposure during pregnancy.
The research team emphasized that their study does not rule out minor risks associated with high levels of opioid exposure but suggests that the link between opioid use and these developmental disorders is weak. They point out that genetic and environmental factors are likely to play a more significant role in the development of autism and ADHD.
“We wanted to conduct this study to help provide more information for pregnant individuals and their physicians who are trying to make complex decisions about how to best manage pain during pregnancy,” said Emma N. Cleary, a researcher involved in the study. “While this study is not able to rule out small increased risks with high amounts of exposure, the results suggest that there is not a causal effect of prescribed opioid analgesics on risk for two common neurodevelopmental disorders.”
Previous research has suggested a connection between prenatal opioid use and ADHD, with a 2019 study indicating that mothers prescribed opioid painkillers were 2.43 times more likely to have children diagnosed with autism. However, the authors of that study cautioned against drawing definitive conclusions, noting that their findings could be influenced by unmeasured factors.
“While our analyses adjusted for several factors known to be associated with both ASD risk and opioid prescription, such as maternal age, smoking, and maternal psychiatric conditions, our estimates could be biased due to unmeasured confounders,” the researchers noted.
In contrast, over-the-counter (OTC) medications, such as acetaminophen, have been scrutinized for their potential link to increased risks of autism and ADHD when used during pregnancy. Nevertheless, comprehensive studies have often found no credible connection between these OTC medications and neurodevelopmental issues.
“Our findings suggest that the observed associations between prenatal exposure to opioid analgesics and two major neurodevelopmental disorders—autism and ADHD—are largely driven by factors leading up to opioid analgesic use rather than the opioid exposure itself,” stated Ayesha C. Sujan, co-author of the study. “These results underline the critical need to provide psychosocial support and evidence-based pain management tools for pregnant individuals experiencing pain.”
As research continues to evolve, it becomes clearer that neither autism nor ADHD can be attributed to a single cause. Studies indicate that these conditions are highly heritable, with genetic factors accounting for 60% to 93% of the risk. Environmental influences also play a role, though they remain poorly understood.
“Pregnant individuals and their physicians must weigh the importance of managing painful conditions against concerns about potential consequences of fetal exposure to prescribed opioid pain medications,” Cleary added. “These concerns include potential impacts on child neurodevelopment.”
The findings of this significant study were published in the journal PLOS Medicine, contributing valuable insights to the ongoing conversation about pain management during pregnancy and its implications for child health.