Key Takeaways

Sample Definition And Size

The study was a nationwide cohort study in Sweden including 2,480,797 singleton liveborn children born between July 1, 1995, and December 31, 2019, with follow-up through December 31, 2021. Among these, 185,909 children (7.49%) were exposed to acetaminophen during pregnancy. A sibling control analysis included 1,773,747 full siblings. ([pubmed.ncbi.nlm.nih.gov](https://pubmed.ncbi.nlm.nih.gov/38592388/?utm_source=openai))

Study Type

Population-based prospective cohort study with sibling control (matched full-sibling) analysis using stratified Cox regression to control for familial confounding. ([pubmed.ncbi.nlm.nih.gov](https://pubmed.ncbi.nlm.nih.gov/38592388/?utm_source=openai))

Conflicts Of Interest

One author disclosed ties to Neobiomics AB; another disclosed ties to law firms and AlphaSights. ([healthday.com](https://www.healthday.com/healthpro-news/child-health/acetaminophen-use-during-pregnancy-not-linked-to-neurodevelopmental-disorders?utm_source=openai))

Results Summary

In conventional models without sibling control, acetaminophen use during pregnancy was associated with marginally increased risks: autism (HR 1.05, 95% CI 1.02–1.08; risk difference at 10 years 0.09%, 95% CI –0.01% to 0.20%), ADHD (HR 1.07, 95% CI 1.05–1.10; RD 0.21%, 95% CI 0.08%–0.34%), and intellectual disability (HR 1.05, 95% CI 1.00–1.10; RD 0.04%, 95% CI –0.04% to 0.12%). In sibling control analyses, there was no association: autism (HR 0.98, 95% CI 0.93–1.04), ADHD (HR 0.98, 95% CI 0.94–1.02), intellectual disability (HR 1.01, 95% CI 0.92–1.10). ([pubmed.ncbi.nlm.nih.gov](https://pubmed.ncbi.nlm.nih.gov/38592388/?utm_source=openai))

Abstract

Acetaminophen use during pregnancy was not associated with children's risk of autism, ADHD, or intellectual disability in sibling control analysis. This suggests that associations observed in other models may have been attributable to familial confounding.

Referenced In

Lee Johnson

a month ago

A Scientific Review of Claims made by RFK Jr.

Claim: A New Study Finding No Link Between Paracetamol/Acetaminophen and Pregnancy is “Garbage”

Validity: Partially true, but misleading.

“The study is a garbage study and it should be retracted. [...] The problem is, the way it determined whether they got Tylenol during pregnancy was by prescriptions. So only 2% of the people in the study got Tylenol during pregnancy, by the endpoint. [...] 50% of the women in Denmark, we know from other studies, actually took Tylenol during pregnancy. So the study was comparing women who took Tylenol during pregnancy to women who took Tylenol during pregnancy.”
WATCH: Health Secretary RFK Jr. testifies about HHS agenda, proposed budget cuts in House hearing

In a House hearing last week, RFK Jr. was asked about a new study showing no link between acetaminophen/paracetamol use during pregnancy and autism. He strongly criticised the research, saying it should be retracted.

But should it?

How the Study Tracked Acetaminophen Use

RFK Jr. is right about the methodology of the study, which was summarized in detail by Contemporary OB/GYN. They used the Danish National Prescription Register to conclude that 2.1% of 1.5 million children born from 1997 to 2022 were exposed to acetaminophen. He cites other research covering 1996 to 2003, showing approximately half of Danish pregnant women taking it.

Research only including Copenhagen, from 2013 to 2019, found that about 10% of pregnant women with chronic diseases and 5% without took it in their first trimester.

Precise estimates vary, but broadly, his comment about the methodology is accurate. The “unexposed” group likely included many women who took acetaminophen.

The goal was simply to use a verifiable measure of exposure, though, so it’s less “should be retracted” and more “has serious limitations.”

How Other Research Clears Things Up

Other research makes it clear that his comment is still highly misleading. A 2024 study from Sweden covered very similar ground, except it included over-the-counter prescriptions too. It ended up with a much bigger “exposed” sample (186k vs. 31k) and also compared siblings where one was exposed to acetaminophen in the womb but the other wasn’t.

They found higher autism rates in those exposed to acetaminophen, but no link at all when comparing siblings with different exposure. The more factors they controlled for, the more the link disappeared.

So RFK Jr. was right that this study is flawed, but better evidence also supports the same conclusion.

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Created: Apr 20, 2026