Rethinking the Link Between Prenatal Acetaminophen and Neurodevelopmental Disorders

A 2025 systematic review sparked a federal health advisory, claiming a strong link between prenatal acetaminophen exposure and neurodevelopmental disorders. According to editorial research analyzed by Groundwork, However, this review relied on qualitative synthesis without quantitative pooling or bias correction. We re-examined the same studies using standard meta-analytic and bias-correction methods to test whether this association holds true.

Methodology and Study Design

We analyzed 24 out of 46 studies from a 2025 Navigation Guide systematic review, which reported a ratio measure (hazard ratio, odds ratio, relative risk, or incidence rate ratio). We collapsed the estimates to one per study, outcome group, and design, resulting in 30 study-level estimates for attention-deficit/hyperactivity disorder (ADHD), autism spectrum disorder (ASD), and other neurodevelopmental disorders. We applied random-effects meta-analysis, eight publication-bias-correction methods, a credibility-ceiling sensitivity analysis, and five quality-filtered subsets. We repeated all analyses after harmonising odds and hazard ratios onto a common risk-ratio scale.

Key Findings and Data Analysis

The association between prenatal acetaminophen exposure and autism spectrum disorder (ASD) attenuated significantly after applying bias-correction methods. The initial estimate of 1.14 (95% CI, 1.01-1.28) dropped to 1.08 (95% CI, 0.97-1.19; P=.17) when each study was weighted equally rather than by its number of sub-analyses. The ADHD association remained positive under most bias-correction methods (range, 1.02-1.31), but its 95% CI crossed 1.00 under a 15% credibility ceiling. The other-NDD association reversed direction under one method (ratio, 0.98; 95% CI, 0.65-1.19) and showed no right-skew on p-curve testing (P=.71).

Our reanalysis challenges the claim of "strong evidence" for an acetaminophen-neurodevelopmental-disorder association. While a modest ADHD association persisted, the ASD and other-NDD estimates moved toward the null. This suggests that the initial findings may have been exaggerated due to methodological limitations.

Implications

The results of our study have significant implications for public health policy and guidelines. The federal health advisory based on the initial review may need to be re-evaluated in light of our findings. Healthcare providers and pregnant women should be aware of the limitations of the existing evidence and make informed decisions about acetaminophen use during pregnancy.

Action Plan

If you are pregnant or planning to become pregnant, it is essential to discuss your acetaminophen use with your healthcare provider. While our study suggests that the link between prenatal acetaminophen exposure and neurodevelopmental disorders may be overstated, it is still essential to follow established guidelines for safe medication use during pregnancy.