Research

Women who take acetaminophen during pregnancy are more likely to have an autistic child.

A growing body of research suggests a consistent association between pregnant women who take acetaminophen and the chance of their child being autistic.

Researchers have demonstrated this association to be robust and meaningful in six independent research studies examining over 105,000 mother and child pairs. Follow-up studies that collected data from previous research found a 20 to 30% increase in the chance of a child having autism if the mother took acetaminophen during her pregnancy when compared to mothers that did not take acetaminophen. Biological assessments of umbilical cord blood and the baby’s first bowel movement have verified this connection and demonstrated a link between the quantity and duration of acetaminophen use and higher rates of autism in children.

Scientific Studies

While many factors can impact the neurodevelopment of children, based on the scientific consensus of the studies reviewed below, acetaminophen use during pregnancy may be a meaningful contributor to the development of autism.

Biological Analyses

Biological assessments of mothers and their children differ from the studies previously outlined because they don't rely on mothers' recollections of acetaminophen use during pregnancy. Instead, these studies measure acetaminophen in meconium–a baby's first stool–and umbilical cord plasma. These same children were then assessed for ASD years later to determine whether there is/was an association between their mother's acetaminophen use during pregnancy and autism in their children.

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Meta Analyses

Meta analyses simultaneously evaluate large numbers of birth cohorts to develop more robust interpretations of available data. Like the birth cohort studies that comprise them, they examine large numbers of mother-child pairs over years and decades to draw reasonable conclusions about the quantitative effects of prenatal exposure to acetaminophen on child development controlling for different environmental, behavioral, and social factors.
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Birth Cohort Analyses

Birth cohort studies examine hundreds or thousands of pregnant mothers and their children over decades to measure differences in child development based on environmental, behavioral, and social factors.

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“I studied the association between the use of talcum powder for genital hygiene and ovarian cancer. The many studies that examined that association are reminiscent of what has been found in research on the association between acetaminophen use during pregnancy and autism diagnoses in children. It is completely irresponsible for drug manufacturers to continue to tell women that acetaminophen is completely safe for use during pregnancy. Pregnant women have a right to know the potential for adverse effects of acetaminophen use.”

- BERNARD HARLOW, PHD (EPIDEMIOLOGIST)

Conclusion

These studies measured acetaminophen use through various collection methods and assessed ASD using a variety of behavioral exams. All come to a similar conclusion: a verifiable, significant, and consistent association between acetaminophen use, autism, and co-occurring diagnoses. Critically, the review of the scientific literature to date reveals that acetaminophen has never been reliably proven to be safe for use in pregnant women.