New review on Tylenol refutes autism risks, despite Trump's claims
Experts warn that limiting Tylenol use during pregnancy could result in inadequate management of health conditions
A recent review of 43 studies published in The Lancet concludes that acetaminophen is not associated with an increased risk of autism, ADHD, or intellectual disabilities in children of pregnant women who use it.
Despite research to the contrary, the Trump administration had promoted the idea of ??a link between Tylenol (the brand name for paracetamol or acetaminophen) and autism, creating confusion about the drug's safety during pregnancy.
Researchers argue that certain studies, which highlight small associations, do not prove causation and are subject to bias. Factors such as genetics, maternal fever, and other prenatal risks are critical in this analysis.
Consequences of discouraging its use
Experts warn that limiting Tylenol use during pregnancy could result in inadequate management of health conditions, posing a risk to both the mother and the fetus.
Its use is safe during pregnancy, stated Dr. Asma Khalil, lead author of the study. "It remains the first-line treatment we would recommend if a pregnant woman experiences pain or fever," reports the Associated Press (AP).
Symptoms that justify its use
Paracetamol is generally considered safe during pregnancy when used under medical supervision for specific symptoms that could affect the health of the mother or fetus if left untreated. Its use is primarily justified for high fever or moderate pain that does not respond to non-pharmacological measures. Always consult a doctor before taking it, prioritizing the lowest effective dose for the shortest possible time.
Avoid its use for mild pain such as mild headaches or minor muscle aches, opting instead for rest, hydration, or cold compresses. Studies associate prolonged use (>4 weeks) with risks such as neurodevelopmental or urogenital disorders, although direct causality has not been proven.In the third trimester, additional risks are assessed, such as preterm birth in cases of preeclampsia.
Genetics and the Risk of Autism and ADHD
Genetics plays a dominant role in the risk of autism spectrum disorder (ASD) and ADHD, with heritability rates estimated between 40-80% for ASD and up to 80% for ADHD, according to reviewed studies. Recent studies, such as meta-analyses in The Lancet and JAMA, indicate that previous associations between prenatal medications (such as paracetamol, valproate, or SSRIs) and these disorders are mostly explained by shared maternal genetic predispositions, not by a direct causal effect of the drug.
Role of Genetics. Disorders such as ASD and ADHD have a multifactorial origin, but familial genetics strongly predisposes: the recurrence risk in siblings reaches 10-20% for ASD. Sibling analyses (same parents, pregnancies with/without drug exposure) eliminate differences in risks, attributing them to shared genetic factors rather than drugs like paracetamol.
Drug evidence. Drugs such as valproate (an antiepileptic) are linked to an increased risk of syndromic autism, but this interacts with pre-existing genetic vulnerabilities. For paracetamol, reviews from 2024-2026 rule out direct links with ASD, ADHD, or intellectual disability after rigorous genetic screening. SSRIs and antibiotics show weak associations, explained by maternal genetics.
Clinical implications. The gene-environment interaction underscores that maternal genetic factors (not the drug per se) mediate observed risks.
Experts recommend evaluating individualized risks/benefits during pregnancy, prioritizing genetics in assessments.
Drug Safety During Pregnancy
Research to determine drug safety during pregnancy follows a rigorous and multifaceted process, prioritizing ethics and fetal protection. It is based on data from preclinical, observational, and, to a lesser extent, controlled clinical studies, since randomized trials in pregnant women are rare for ethical reasons.
Early Stages. Studies begin with animal testing to assess reproductive toxicity and teratogenic effects, classifying risks into categories such as A (safe) to X (contraindicated) according to systems such as that of the Food and Drug Administration (FDA). This preclinical data identifies potential harms before any human exposure.
The main evidence comes from prospective cohorts, exposure registries (where exposed pregnant women are enrolled and their pregnancies are monitored), case-control studies, and meta-analyses of epidemiological databases.Organizations such as the Centers for Disease Control and Prevention (CDC) analyze usage patterns to balance risks and benefits.
Current ethical guidelines. Initiatives such as the ICH E21 guideline promote ethical clinical trials in pregnant women when the benefits justify the exposure, addressing legal and scientific barriers to generating specific data. Informed consent and risk-benefit assessment are central.