The question of whether **painkillers taken during pregnancy raise the risk of autism** in children is complex and has been the subject of extensive research. Current authoritative evidence indicates that **common prescribed opioid painkillers during pregnancy do not cause an increased risk of autism spectrum disorder (ASD)** or attention-deficit/hyperactivity disorder (ADHD) in children, although some uncertainty remains for very high exposures, which are rare**[1]**. For acetaminophen (paracetamol), widely used as an over-the-counter painkiller and fever reducer during pregnancy, the evidence is mixed and evolving, with regulatory agencies taking a cautious but not alarmist stance.
### Opioid Painkillers and Autism Risk
A large retrospective study from Indiana University, published in *PLOS Medicine* in 2025, analyzed data from Sweden and found **no causal link between prescribed opioid analgesics during pregnancy and increased risk of autism or ADHD in children**[1]. The study suggests that observed associations in some earlier research may be explained by other confounding factors, such as underlying maternal health conditions or genetics, rather than the opioid exposure itself. The authors emphasize that while very high opioid exposure might carry some risk, such cases are rare and the overall evidence does not support a direct causal effect.
This study is significant because it uses large-scale population data and advanced statistical methods to control for confounders, providing reassurance to pregnant individuals and clinicians about the safety of medically supervised opioid use for pain management during pregnancy.
### Acetaminophen (Paracetamol) and Autism Risk
Acetaminophen is the most commonly recommended over-the-counter pain and fever medication during pregnancy due to its generally favorable safety profile. However, in recent years, several observational studies have reported **associations between prolonged or high-dose acetaminophen use during pregnancy and increased risks of neurodevelopmental disorders, including autism and ADHD**[2]. These studies include large cohorts such as the Nurses’ Health Study II and the Boston Birth Cohort.
In response, the U.S. Food and Drug Administration (FDA) has initiated a process to update acetaminophen labeling to reflect this emerging evidence, advising caution and encouraging healthcare providers and pregnant individuals to weigh the benefits and risks carefully[2]. The FDA stresses that while an association has been observed, **a causal relationship has not been established**, and acetaminophen remains the only over-the-counter medication approved for fever reduction during pregnancy, which is important because high maternal fever itself can harm fetal development.
### Position of Global Health Authorities
The World Health Organization (WHO) has reviewed the evidence and states that **there is currently no conclusive scientific proof linking acetaminophen use during pregnancy to autism**[3]. WHO recommends that pregnant women follow medical advice carefully and use any medication, including acetaminophen, only when necessary and under professional guidance. They emphasize that autism is a complex condition with multiple contributing factors, and no single cause has been definitively identified.
Similarly, the European Medicines Agency (EMA) and Australia’s Therapeutic Goods Administration (TGA) maintain that **paracetamol remains an important and generally safe option for managing pain and fever during pregnancy**, based on rigorous assessments of available data[4][5]. They advise cautious use but do not recommend avoiding it outright.
### Understanding the Evidence and Limitations
– **Observational studies dominate this field** because randomized controlled trials (RCT
