A comprehensive study involving over two million individuals has determined that there is no significant correlation between the use of opioid painkillers during pregnancy and the risk of developing autism spectrum disorder (ASD) or attention-deficit/hyperactivity disorder (ADHD). This research, conducted by scientists at Indiana University Bloomington, challenges earlier studies suggesting a potential link between prenatal opioid exposure and these neurodevelopmental conditions.
The researchers analyzed health records of more than 1.2 million children born in Sweden between 2007 and 2018. They focused on the rates of ASD among mothers who used opioid painkillers during pregnancy. Additionally, they examined another group of approximately 900,000 children born between 2007 and 2015 to assess the prevalence of ADHD.
Findings showed that 2% of children born to mothers with no opioid use received an autism diagnosis by age ten. In comparison, 2.9% of children exposed to a low dose of prescribed painkillers in utero were diagnosed with autism. The rate increased to 3.9% for those exposed to higher doses. A similar trend was observed in ADHD diagnoses, although the study did not evaluate the effects of extremely high doses or prolonged use of the medication.
According to Emma N. Cleary, a researcher involved in the study, the results indicate that the perceived increased risk of neurodevelopmental disorders diminishes when considering other influencing factors. “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,” Cleary stated. The researchers emphasized that genetic and environmental factors are likely to have a more significant impact on the development of ASD and ADHD than opioid exposure itself.
In light of their findings, the team applied statistical methods to account for variables such as maternal age, smoking, and psychiatric conditions. After adjusting for these factors, the supposed increased risk associated with opioid use during pregnancy was no longer evident.
Earlier research had suggested a connection between prenatal opioid use and a heightened risk of ADHD, with a 2019 study indicating that mothers prescribed opioids were 2.43 times more likely to have children diagnosed with autism. However, the authors of that study acknowledged the need for caution, stating, “While our analyses adjusted for several factors known to be associated with both ASD risk and opioid prescription, our estimates could be biased due to unmeasured confounders.”
The current study also highlights the ongoing debate surrounding over-the-counter (OTC) pain medications, such as acetaminophen, which have been implicated in raising the risk of autism and ADHD during pregnancy. Nevertheless, comprehensive investigations have often negated any credible link between OTC medications and neurodevelopmental issues.
Co-author Ayesha C. Sujan remarked, “Our findings suggest that the observed associations between prenatal exposure to opioid analgesics and two major neurodevelopmental disorders are largely driven by factors leading up to opioid analgesic use rather than the opioid exposure itself.” This underscores the necessity for providing pregnant individuals with appropriate psychosocial support and evidence-based pain management options, which may include both pharmaceutical and non-pharmaceutical approaches.
The study concludes that neither autism nor ADHD can be attributed to a single cause. Research indicates that both conditions are highly heritable, with genetic factors accounting for approximately 60% to 93% of the risk. Additionally, social and environmental influences remain inadequately understood.
Cleary emphasized the importance of balancing the management of pain during pregnancy with concerns about potential impacts on fetal neurodevelopment. The study’s findings were published in the journal PLOS Medicine, adding valuable data to the discussion surrounding opioid prescriptions for pregnant individuals.
