Maternal use of acetaminophen during pregnancy and risk of autism spectrum disorders in childhood: A Danish national birth cohort study.
Long acetaminophen use during pregnancy may slightly raise the chance of autism with hyperactive features—share this with expectant mothers so they can limit use.
01Research in Context
What this study did
Liew et al. (2016) tracked Danish mothers who took acetaminophen while pregnant. They asked if the drug raised the chance of having a child later diagnosed with autism.
Doctors looked at pharmacy records and national autism registries. They compared kids whose moms used the painkiller for many weeks with kids whose moms used it little or not at all.
What they found
Children exposed to acetaminophen for more than 20 weeks in the womb had a slightly higher chance of autism with hyperactive traits. The link was modest and did not show up for other autism profiles.
Shorter use or use only in early pregnancy showed no clear extra risk.
How this fits with other research
Connolly et al. (2016) ran a similar 2016 registry study and saw the same small bump in autism odds from maternal obesity and diabetes. Both papers point to modest prenatal risk factors, not causes.
Danitz et al. (2014) found a small autism signal after longer SSRI use, matching the dose-response pattern Zeyan saw with acetaminophen. The two drugs differ, but the story is the same: longer exposure, slightly higher odds.
Whitehouse et al. (2014) looked protective: regular prenatal vitamins cut autistic-like behaviors by roughly half. Zeyan’s acetaminophen finding moves the needle in the opposite direction, reminding us that some prenatal choices raise risk while others lower it.
Why it matters
You cannot change a child’s prenatal history, but you can guide families who are planning more children. When a parent asks about safe pain relief during pregnancy, share Zeyan’s finding: long-term acetaminophen use carries a small autism-plus-hyperactivity signal. Encourage them to weigh this against their doctor’s advice and to limit use to the shortest effective time.
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02At a glance
03Original abstract
Acetaminophen (paracetamol) is the most commonly used pain and fever medication during pregnancy. Previously, a positive ecological correlation between acetaminophen use and autism spectrum disorders (ASD) has been reported but evidence from larger studies based on prospective data is lacking. We followed 64,322 children and mothers enrolled in the Danish National Birth Cohort (DNBC; 1996-2002) for average 12.7 years to investigate whether acetaminophen use in pregnancy is associated with increased risk of ASD in the offspring. Information on acetaminophen use was collected prospectively from three computer-assisted telephone interviews. We used records from the Danish hospital and psychiatric registries to identify diagnoses of ASD. At the end of follow up, 1,027 (1.6%) children were diagnosed with ASD, 345 (0.5%) with infantile autism. We found that 31% of ASD (26% of infantile autism) have also been diagnosed with hyperkinetic disorders. More than 50% women reported ever using acetaminophen in pregnancy. We used Cox proportional hazards model to estimate hazard ratio (HR) and 95% confident interval (CI). Prenatal use of acetaminophen was associated with an increased risk of ASD accompanied by hyperkinetic symptoms (HR = 1.51 95% CI 1.19-1.92), but not with other ASD cases (HR = 1.06 95% CI 0.92-1.24). Longer duration of use (i.e., use for >20 weeks in gestation) increased the risk of ASD or infantile autism with hyperkinetic symptoms almost twofold. Maternal use of acetaminophen in pregnancy was associated with ASD with hyperkinetic symptoms only, suggesting acetaminophen exposure early in fetal life may specifically impact this hyperactive behavioral phenotype. Autism Res 2016, 9: 951-958. © 2015 International Society for Autism Research, Wiley Periodicals, Inc.
Autism research : official journal of the International Society for Autism Research, 2016 · doi:10.1002/aur.1591