Tylenol in Pregnancy: What the Science Really Says (and Why You Can Stop Panicking)

By Dr. Pete, Emergency Physician, Professor, and Relentlessly Practical Dad

In 2025, the U.S. Department of Health and Human Services, under Secretary RFK Jr., stirred a media storm by suggesting that taking Tylenol (acetaminophen) during pregnancy might increase the risk of autism.

If you are pregnant or planning to be, the headlines were… unsettling. At least one cable news network managed to fit the words “pregnancy,” “autism,” and “toxic” in the same graphic, ensuring no expectant parent slept well that night.

So — is this a real risk, or is this another episode of The Internet Is Terrified?

Let’s look at what the best, most current scientific evidence actually shows.

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First: What Started the Panic?

The claim is that mothers who use Tylenol during pregnancy have children with higher rates of autism or ADHD. This idea didn’t come from nowhere — there are older observational studies showing small statistical associations.

But here’s the central issue:

Association is not causation.

If every parent who ever used Tylenol created autism, pediatric clinics would look like stadium concerts. Given how common Tylenol use is in pregnancy — historically reported by 50–65% of women — we would have noticed a dramatic pattern decades ago.

Before restricting a medication that many pregnant people rely on for fever and pain management, scientists asked the harder questions.

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The Biggest, Best Study: Nearly 2.5 Million Children

In a landmark analysis published in JAMA, researchers followed 2,480,797 children born in Sweden between 1995 and 2019 (Ahlqvist 2024). This is currently the gold standard of evidence on this topic.

The researchers examined rates of autism, ADHD, and intellectual disability.

Here is what they found:

• Simple comparisons: Moms who used Tylenol had kids with slightly higher rates of these diagnoses.

• Sibling test: The researchers then compared siblings — one exposed to Tylenol in utero and one not.

Sibling comparisons are scientifically powerful. They automatically control for genetics, family environment, parenting styles, diet, maternal age, socioeconomic status, and environmental exposures — factors that usually confuse the data.

Once they compared siblings, the differences vanished.

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Here are the results, measured in “Hazard Ratios”:

• Autism: Hazard Ratio 0.98

• ADHD: Hazard Ratio 0.98

• Intellectual disability: Hazard Ratio 1.01

What does “Hazard Ratio” mean?

Think of a Hazard Ratio as a risk scorecard:

• 1.0 = same risk

• Above 1.0 = higher risk

• Below 1.0 = lower risk

A score of 0.98 is effectively 1.0.

It means that statistically, there is no difference in risk between the siblings.

This is the scientific equivalent of:

“We looked closer, and the scary thing disappeared.”

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Compounding Evidence

This wasn’t a one-off finding.

Another major study published in JAMA Pediatrics (Yland 2024) looked at acetaminophen use regarding sleep and neurodevelopment, and similarly found that when researchers accounted for “confounding by indication” — the reason why the mother took the medicine — the risks diminished or disappeared.

The consensus from the highest quality data is that the condition causing the pain (fever, inflammation, underlying illness) is likely the culprit — not the pill used to treat it.

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Why Those Earlier Studies Looked Concerning

Older studies suggested a link because they suffered from confounding.

Fever, infections, chronic inflammation, and severe stress can all affect fetal brain development.

If a mother takes Tylenol because she has a high fever (which is dangerous for a fetus), and the child later has a neurodevelopmental diagnosis — was it the Tylenol or the fever?

Older studies couldn’t tell.

The newer sibling-matched data strongly suggest it was the underlying health factors, not the medication.

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What Do Expert Groups Say?

Despite the 2025 news cycle, medical societies have maintained a clear stance based on data, not fear:

• ACOG maintains that acetaminophen is the only appropriate analgesic for use during pregnancy when necessary. They emphasize that untreated fever and pain carry their own risks to the pregnancy (ACOG 2024).

• SMFM concurs, stating that the evidence does not support changing clinical practice or avoiding acetaminophen when indicated.

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So, What Should Parents Do?

Here is the practical, evidence-based guidance:

Use Tylenol only when you need it, at the lowest dose that helps, for the shortest time necessary.

This isn’t because Tylenol is “toxic,” but because no medication should be used casually in pregnancy.

Examples:

✔️ Persistent headache:
Take a dose. Pain causes stress, which releases cortisol — not great for baby.

✔️ Fever:
Definitely treat it. High fever is a proven teratogen (it can harm the fetus). Reducing fever is protective.

✔️ Mild discomfort:
If it improves with rest, fluids, or a snack?
You can skip the medication.

Using Tylenol “just in case” or for minor aches that are tolerable is not necessary. But suffering through high fevers or debilitating pain out of fear is not safer — it’s actually riskier.

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The Bottom Line

• No high-quality evidence shows that Tylenol causes autism.

• The strongest study in history — nearly 2.5 million children — found no increased risk when genetic and family factors were properly controlled.

Pregnancy comes with enough rules:

• avoid sushi

• skip the hot tub

• sleep on your side

• take your vitamins

You do not need to add “fear of Tylenol” to that list.

Use it if you need it. Skip it if you don’t. That’s the science. When in doubt, consult your physician always.

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References

Ahlqvist VH, Sjöqvist H, Dalman C, et al. Acetaminophen use during pregnancy and children’s risk of autism, ADHD, and intellectual disability: a population-based cohort study. JAMA. 2024;331(14):1205-1214.

Yland JJ, Bateman BT, Friedlander Y, et al. Acetaminophen use during pregnancy and neurodevelopmental outcomes: the role of confounding by indication. JAMA Pediatr. 2024;178(6).

American College of Obstetricians and Gynecologists (ACOG). Clinical Guidance: Acetaminophen Use During Pregnancy. Reaffirmed 2024.

Society for Maternal–Fetal Medicine (SMFM). SMFM Statement: Response to claims regarding acetaminophen use in pregnancy. 2024.

National Institutes of Health. NIH study finds no evidence that acetaminophen use in pregnancy causes autism or ADHD in children. April 9, 2024.

Author’s Note on Content Creation
I use AI tools like ChatGPT and Gemini in an iterative workflow to help with reference cross-checking, fact validation, and initial drafts. The final tone, structure, humor, and all opinions remain my own as an emergency physician, educator, and parent. These articles reflect my writing, my judgment, and my voice—with a little help from the robots.