When public figures make bold statements about medication risks in pregnancy, especially involving autism, it can trigger real alarm among patients. Pregnancy is a unique and vulnerable time in a person’s life, filled with concern about keeping the baby safe. And when it comes to interpreting scientific data, whether about medications or any other exposures, the nuances often get lost in lay media. It can be hard to know what to believe.
As clinicians, one of our primary responsibilities is to help interpret what the science has proven versus what remains unproven, so that our patients can make informed decisions, rather than fear-based ones. Below, we have reviewed and summarized what the best available evidence says about acetaminophen (Tylenol™/paracetamol) and autism (and other neurodevelopmental conditions), common misunderstandings, and practical guidance.
It’s widely used: 40–65% of pregnant individuals report acetaminophen use
It’s safer than alternatives:
- NSAIDs can increase miscarriage risk or cause ductus arteriosus closure.
- Opioids carry dependence and withdrawal risks.
- Gabapentinoids lack strong safety data.
Untreated fever and pain matter: Maternal fever is linked to neural tube defects, congenital heart disease, and miscarriage. Safe symptom relief is essential for both mom and baby.
1. The Large Swedish Cohort / Sibling Control Study (JAMA 2024)
This is one of the most powerful and carefully controlled studies to date. The cohort comprised 2,480,797 children born in Sweden between 1995 and 2019, with follow-up through 2021. Acetaminophen exposure was prospectively recorded from antenatal and prescription records.
In models that did not control for familial factors, like genetics or the environment a child grew up in, there were small increased risks for autism, ADHD, and intellectual disability among exposed children. For example, hazard ratios* (HRs) ~1.05‑1.07 for autism or ADHD. However, in sibling‑control analyses (comparing exposed vs. unexposed siblings, which helps control for many shared familial confounders), no statistically significant increased risk was found.
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)
This study's findings argue against a causal link between acetaminophen exposure in utero and autism based on current data.
*A hazard ratio is used when researchers compare how often an event happens in one group versus another over time. For example, a hazard ratio of 1.5 means the outcome showed up about 50% more often in one group. Hazard ratios are about relative rates over time, not raw probabilities. They’re most meaningful when paired with absolute risks or survival curves.
2. Systematic Review Using the Navigation Guide (Mount Sinai / Baccarelli et al., 2025)
This review examined 46 observational studies as of early 2025, using the Navigation Guide methodology to assess the risk of bias and the strength of evidence. The results of this systematic review were varied. Many studies reported associations between prenatal acetaminophen use and increased risk of neurodevelopmental disorders, especially ADHD and autism. Some studies did not find associations; a few even reported negative or inverse associations. Several studies reported dose‑response relationships (more or longer acetaminophen use correlating with a higher risk) in certain designs.
The authors identified widespread methodological limitations, which confounded the findings, including:
Reliance on maternal self‑reporting for acetaminophen use (frequency, dose, timing). Self-reporting, as we know, can lead to misestimation of exposure.
Differences in outcome measurement (diagnosis vs. parent‑report vs. biomarkers), exposure windows, doses, and follow‑up time.
Confounding by indication, meaning the reason the patient took the acetaminophen itself could contribute to neurodevelopmental risk (fever, infection, etc.).
Overall, the authors of this review judged that the associations warrant “caution;” there is not strong enough evidence to claim causality. They recommended tailoring the shared decision between clinician and patient and using acetaminophen judiciously, using the lowest effective dose for the shortest amount of time.
To be really clear, because this is where misinformation often slips in, there is no definitive causal link between acetaminophen use in pregnancy and autism that has been established.
The strongest study to date (the Swedish sibling cohort) found no increased risk when familial confounding is controlled. The studies that have shown a small increased risk are in non‑controlled observational models, which are vulnerable to bias such as confounding by indication, recall bias, or misclassification.
Evidence remains inconsistent about dose, timing, and which pregnancies (or which parts of the brain’s development) might be vulnerable. The risk, if it exists, appears to be small in absolute terms. For example, in the Swedish cohort, the risk difference at 10 years of age for autism (ever exposed vs. never) was ~0.09% higher. However, this small increase disappeared in sibling comparisons.
ACOG (American Academy of Obstetricians and Gynecologists): A 2025 Obstetrics & Gynecology clinical perspective concluded that associations in many studies linking prenatal acetaminophen use and autism weaken or vanish when controlling for familial/genetic factors. They cite robust studies like the Swedish cohort study when they make their statement, “In utero exposure to acetaminophen is unlikely to confer a clinically important increased risk of childhood ADHD or ASD.”
SMFM (Society for Maternal-Fetal Medicine): SMFM on September 5, 2025, reaffirms that acetaminophen is appropriate for treating pain and fever during pregnancy. They state that although some studies suggest associations with autism/ADHD, no causal link is established.
SOGC (Society of Obstetricians and Gynaecologists of Canada): SOGC on September 12, 2025, reaffirmed their recommendation that acetaminophen is the first-line option for fever and pain during pregnancy when medically indicated, at recommended doses, for the shortest duration. They state the evidence for causality is weak and should not change clinical practice.
FDA (The U.S. Food and Drug Administration): Updated on August 14, 2025, the FDA states that, “To date, FDA has not found clear evidence that appropriate use of acetaminophen during pregnancy causes adverse pregnancy, birth, neurobehavioral, or developmental outcomes.”
Given the current evidence, here are principles and talking points to guide conversations with pregnant patients, balancing risk, benefit, and uncertainty:
Acknowledge uncertainty. It’s okay to say, “Right now, science does not show that using acetaminophen in pregnancy causes autism. Researchers are still looking at this. Some earlier studies suggested a possible link, but later, better-designed studies didn't show any increased risk.” This honesty builds trust.
Emphasize that untreated fever, pain, or infection itself can be harmful during pregnancy. So acetaminophen is often the safer option for managing those symptoms.
Use the lowest effective dose for the shortest duration needed. Minimize unnecessary exposure, if possible, but avoid undertreating real pain or fever.
Current best evidence does not support that acetaminophen taken during pregnancy causes autism. The large sibling‑control study suggests that any increased risks seen elsewhere are likely due to confounding. Associations in some studies warrant caution and ongoing investigation, but we are not yet at the point of changing the standard of care broadly. Clinical guidance should remain nuanced: use acetaminophen in pregnancy when needed, in appropriate doses, after weighing risks vs. benefits, and with patient‑centered communication.