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Beginning with a press conference<\/a> about autism in September \u2014 the Kennedy-imposed<\/a> deadline for knowing the cause of the \u201cautism epidemic\u201d \u2014 President Donald Trump has repeatedly<\/a> told pregnant women<\/a> not to take Tylenol<\/a> unless \u201cabsolutely necessary<\/a>.\u201d Kennedy has been a bit more circumspect on the topic, speaking<\/a> of a \u201cpotential association\u201d between prenatal Tylenol, also known as acetaminophen, and later autism diagnoses in children and calling<\/a> the literature finding a connection \u201cvery suggestive.\u201d<\/p>\n As we wrote<\/a> in September<\/a>, some studies have shown an association between prenatal acetaminophen use and autism. However, experts told us that these associations were likely not causal, and instead probably due to traits shared among people who tend to take more acetaminophen in pregnancy, such as a hereditary susceptibility to autism.<\/p>\n The new Danish study<\/a>, published April 13 in JAMA Pediatrics, looked at national prescription fulfillment records for mothers of more than 1.5 million children and corresponding health records, finding no association between taking acetaminophen or taking greater doses of the drug during pregnancy and later autism diagnoses in the children.<\/p>\n When asked about the Danish study at the House Education and Workforce Committee hearing on April 17, Kennedy moved to discredit it. \u201cThe study is a garbage study. It should be retracted,\u201d he told<\/a> Republican Rep. Virginia Foxx of North Carolina. Kennedy went on to criticize the study for relying on prescription records when acetaminophen is also available over the counter. \u201cIt was a garbage in, garbage out study,\u201d Kennedy continued. \u201cThe industry has the capacity to generate these studies all the time, and it\u2019s fraudulent. It should be retracted.\u201d<\/p>\n The study did rely on prescription data, which can lead to incomplete data on the use of the drug, Dr. Kira Philipsen Prahm, a doctor in the Center for Fetal Medicine at the Copenhagen University Hospital Rigshospitalet and first author of the study, told us via email. But such a limitation \u201cdoes not automatically invalidate results,\u201d she said. \u201cThe key question is whether the misclassification is likely to meaningfully bias the findings.\u201d Her team\u2019s analyses, along with prior research, indicate that \u201cif there were a strong causal effect\u201d of acetaminophen on autism, \u201cit would be unlikely to be entirely obscured by this limitation,\u201d she said.<\/p>\n Brian Lee<\/a>, a professor of epidemiology at Drexel University\u2019s Dornsife School of Public Health, told us that most acetaminophen<\/a> is prescribed in Denmark, following restrictions on how much of the medication can be sold without a prescription. This makes Denmark a relatively good location to do a prescription-based study, he said, contrary to Kennedy\u2019s implication that the approach invalidated the study. These restrictions were in place during the latter years of the study.<\/p>\n Furthermore, Prahm said, her team\u2019s study did not find \u201ca pattern suggesting increased risk with greater recorded exposure.\u201d If acetaminophen were causing autism, one would expect to see more cases with increasing doses.<\/p>\n Nor are papers retracted simply because they have limitations, which all studies have. Prahm and her colleagues wrote in their paper that information about individuals\u2019 over-the-counter acetaminophen use was missing and that \u201cthus, the true exposure level among those with low-level exposure was likely underestimated,\u201d while also explaining why they thought this was unlikely to have introduced meaningful bias.<\/p>\n Kennedy has a history of trying to \u201cwield his considerable influence\u201d to \u201cforce a retraction of a study without a legitimate reason,\u201d Lee said, referring to a study about a common vaccine ingredient Kennedy said<\/a> last summer should be retracted.<\/p>\n Legitimate reasons for retraction, Lee said, would include \u201canalytical errors that affect the qualitative conclusions of the study, integrity issues, or loss in confidence of findings by the authors.\u201d Prahm\u2019s study \u201cdoes not appear to feature any of these issues,\u201d he said, calling Kennedy\u2019s calls for retraction \u201cunwarranted and politically coercive.\u201d Lee was co-author of a 2024 Swedish study<\/a> that pointed away from a causal association between prenatal acetaminophen use and autism in children, but he was not involved in the new Danish study.<\/p>\n Dr.\u00a0Per Damkier<\/a>, a professor in the department of clinical research at the University of Southern Denmark, told us via email that Kennedy \u201cis well outside his domain of expertise\u201d in assessing the scientific merits of the study. Damkier was not involved in the new study but has studied acetaminophen use during pregnancy.<\/p>\n Prahm said that the study was \u201cconducted using nationwide Danish registry data and the pharmaceutical industry was not involved in funding or any other part of the study.\u201d The study lists Danish governmental and hospital funding. One of the nine authors disclosed funding by a pharmaceutical company for unrelated work evaluating a contraceptive pill.<\/p>\n HHS did not reply to a request asking for the basis for Kennedy\u2019s claims about the Danish study.<\/p>\n Missing Context on Acetaminophen in Denmark<\/p>\n Kennedy faulted the Danish study for using prescription data and for the low percentage of women it recorded as using acetaminophen. \u201cOnly 2% of the people in this study got Tylenol during pregnancy, according to the endpoint,\u201d Kennedy told<\/a> lawmakers. \u201cIn fact, we know, because Tylenol is available by over the counter, most of you have taken Tylenol. Very few of you have ever gotten a prescription.\u201d<\/p>\n But Kennedy was missing context on acetaminophen in Denmark, which has been increasingly obtained via prescription in recent years.<\/p>\n \u201cReliance on prescription records alone would be bad in a setting like the US, where most acetaminophen use is\u201d over the counter, Lee said. \u201cHowever, Denmark is not the US.\u201d<\/p>\n Damkier said that before 2014, \u201cmore than 60% of all acetaminophen sold in Denmark\u201d was over the counter. But in late 2013, Denmark limited the quantity of acetaminophen that could be sold without a prescription. Following this change, \u201cmore than 80% of acetaminophen sold has been prescription based,\u201d he said, citing his own\u00a0research<\/a>\u00a0on the topic. \u201cI believe exposure data from 2014 and onwards are valid and representative with low risk\u201d of misclassifying acetaminophen use, he said.<\/p>\n The new study looked at prescription records from pregnancies for children born between 1997 to 2022. Damkier said that the study \u201ccan be criticized\u201d for using prescription data prior to the change in prescription regulations but that he believes \u201cthe conclusions of the authors are substantiated\u201d overall. \u201cBy and large, this large population-wide study supports the findings from the most recent studies: Exposure to acetaminophen during pregnancy is not associated with an increased risk of childhood\u201d autism, he said.<\/p>\n Prahm said that she and her co-authors had done further analyses to see if the findings varied before or after 2013, but the team \u201cfound no statistical differences between the two periods.\u201d<\/p>\n Kennedy also provided<\/a> a relatively high-end estimate for acetaminophen use during pregnancy in Denmark. \u201cFifty percent of the women in Denmark, we know from other studies, actually took Tylenol during pregnancy,\u201d Kennedy said. \u201cSo the study was comparing people, women who took Tylenol during pregnancy to women who took Tylenol during pregnancy.\u201d<\/p>\n HHS did not reply to a question about where Kennedy got this statistic, but older, self-reported\u00a0data<\/a>\u00a0from the Danish National Birth Cohort found this relatively high rate of use.\u00a0Estimates of acetaminophen use during pregnancy vary, and one\u00a0more recent\u00a0study<\/a>\u200b found that 6% of women reported using the medication during the first trimester.<\/p>\n Lee said that many women in the Danish National Birth Cohort study were missing responses on acetaminophen use and were not included, saying that \u201cthe 50% is almost assuredly an overestimate.\u201d<\/p>\n Furthermore, Lee and Prahm both objected to Kennedy\u2019s characterization of the new study as comparing \u201cwomen who took Tylenol during pregnancy to women who took Tylenol during pregnancy.\u201d<\/p>\n \u201cThat is not an accurate description of the study design,\u201d Prahm said. \u201cWhile some individuals classified as unexposed may in fact have used over-the-counter acetaminophen, this does not mean the two groups are equivalent.\u201d <\/p>\n Pros and Cons of Prescription Data<\/p>\n The Danish study is not alone<\/a> in using<\/a> prescription data. Lee explained that using prescription data has \u201cadvantages and disadvantages.\u201d An advantage is that it provides an objective record of drug supply, whereas studying over-the-counter exposure requires asking people to report on their own use, he said. <\/p>\n People can misreport their medication use, Prahm said, or the data can be influenced by recall bias, a phenomenon<\/a> where people can remember things differently depending on later events. For example, a parent with a child diagnosed with autism might remember their medication use during pregnancy differently than a parent without this experience.<\/p>\n Furthermore, while prescription-based studies do miss some exposures to acetaminophen, they are likely to capture the most impactful use.<\/p>\n \u201cPrescription based exposure likely captures those women who use substantial amounts of acetaminophen as opposed to [over-the-counter] based use, which tends to be low and sporadic,\u201d Damkier said. \u201cIf there is no signal for prescription-based use, it is consequently exceedingly unlikely that sporadic [over-the-counter] use be associated with an increased risk\u201d of autism.<\/p>\n Regardless, researchers don\u2019t rely on single studies to draw conclusions. Rather, they look for a pattern of replication among studies done using various methods and datasets, David S. Mandell<\/a>, a psychiatry professor at the University of Pennsylvania Perelman School of Medicine and director of the Center for Mental Health Policy and Services Research, told us via email. \u201cWhen we see replication, we grow more confident in the findings.\u201d<\/p>\n Multiple studies have found that associations between prenatal acetaminophen use and neurodevelopmental conditions go away<\/a> when<\/a> comparing siblings<\/a>. In recent months, two review<\/a> studies<\/a> have pulled together the available data, concluding that the evidence does not show any clear or \u201cclinically important\u201d link between prenatal exposure to the medication and autism.<\/p>\n \u201cWe now have studies from Nordic countries, Japan and Taiwan showing that Tylenol doesn\u2019t cause autism,\u201d Mandell said. The degree of acetaminophen use varied in the studies, \u201cand it doesn\u2019t make a difference in the findings.\u201d<\/p>\n Prahm emphasized that her team aimed to \u201ccontribute one piece of evidence\u201d to be interpreted in the context of the broader literature. \u201cOverall, the current evidence does not establish a clear association,\u201d she said.<\/p>\n Editor\u2019s note:\u00a0FactCheck.org does not accept advertising. We rely on grants and individual donations from people like you. Please consider a donation. Credit card donations may be made through\u00a0our \u201cDonate\u201d page<\/a>. If you prefer to give by check, send to: FactCheck.org, Annenberg Public Policy Center, P.O. Box 58100, Philadelphia, PA 19102.\u00a0<\/p>\n","protected":false},"excerpt":{"rendered":"During an April 17 congressional hearing, Health and Human Services Secretary Robert F. Kennedy Jr. called for retraction…\n","protected":false},"author":2,"featured_media":616648,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[58],"tags":[97,243],"class_list":["post-616647","post","type-post","status-publish","format-standard","has-post-thumbnail","category-medication","tag-health","tag-medication"],"_links":{"self":[{"href":"https:\/\/www.newsbeep.com\/us\/wp-json\/wp\/v2\/posts\/616647","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.newsbeep.com\/us\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.newsbeep.com\/us\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/us\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/us\/wp-json\/wp\/v2\/comments?post=616647"}],"version-history":[{"count":0,"href":"https:\/\/www.newsbeep.com\/us\/wp-json\/wp\/v2\/posts\/616647\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/us\/wp-json\/wp\/v2\/media\/616648"}],"wp:attachment":[{"href":"https:\/\/www.newsbeep.com\/us\/wp-json\/wp\/v2\/media?parent=616647"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.newsbeep.com\/us\/wp-json\/wp\/v2\/categories?post=616647"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.newsbeep.com\/us\/wp-json\/wp\/v2\/tags?post=616647"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}![\"\"](\"https:\/\/www.newsbeep.com\/us\/wp-content\/uploads\/2026\/05\/acetaminophen-400x267-1.jpg\")
Photo by Ronaldo Schemidt \/ AFP via Getty Images.<\/p>\n