Study: Children Whose Mothers Took Acetaminophen During Pregnancy More Likely To Have ADHD, Autism

Babies of women who took acetaminophen—a common painkiller marketed in the U.S. under the brand name Tylenol—near the end of pregnancy had a higher likelihood of being diagnosed with autism spectrum disorders or with attention deficit hyperactivity disorder (ADHD), according to a study published Wednesday in JAMA Psychiatry.

The study, conducted by researchers from the Johns Hopkins University Bloomberg School of Public Health, cross referenced blood samples taken from the mother after the baby's birth and samples taken from the babies' umbilical cords, which were used to assess how much acetaminophen the mother had ingested.

A mother-to-be who takes Tylenol during their pregnancy is liable to have some of the medication reach a developing fetus, as the drug has been demonstrated to cross the placenta, according to United Press International (UPI).

The children involved in the study were reexamined when they were around 10 years old. Researchers found that those children whose umbilical cords had contained higher levels of acetaminophen were significantly more likely to have an autism spectrum disorder or ADHD than the children who did not appear to have been exposed to acetaminophen in utero.

According to UPI's analysis of the findings, "the odds of these developmental disorders were more than twice as high in children exposed to acetaminophen near the time of birth. The association was strongest between exposure to acetaminophen and ADHD in the child."

According to the study, out of the 996 children studied, 257 (25.8 percent) had ADHD only, while 66 (6.6 percent) were only on the autism spectrum. Another 42 children (4.4 percent) had both autism and ADHD, and 304 (30.5 percent) had other developmental disabilities. The remaining 327 (32.8 percent) were neurotypical, meaning that they had no discernible developmental disabilities.

This study is meaningful because it supports previous research that suggested a link between acetaminophen use during pregnancy and development disabilities. Whereas most studies have relied on reporting of developmental disabilities from the mothers, the Johns Hopkins researchers linked the correlation to measurable chemical evidence.

Dr. Xiaobin Wang, a senior author of the study, told UPI that while the association between acetaminophen is consistent, more research needs to be done to determine whether the correlation is a result of causation or something more.

Further, the demographics used for this study should be noted. In this case, researchers examined data of 996 mother-infant pairs from the Boston Birth Cohort, a group used to study the factors that impact healthy pregnancy and childhood development. This was only a sampling of the full cohort, which, according to John Hopkins, included 8,500 mother-infant pairs from Boston who were mostly of African American (65 percent) or Hispanic (25 percent) descent. Further, slightly more than half of the children (55 percent) examined for the Tylenol study were males.

Speaking to the Philadelphia Inquirer, Dr. Joseph McCleery an autism researcher and assistant professor of psychology at St. Joseph's University, said that the findings were useful, even if the Boston Birth Cohort did not necessarily represent a good sampling of the general population.

"There's a lot more work to be done here, but they show a solid relationship of likely perinatal use of acetaminophen and higher risk" of autism spectrum disorder and ADHD, McCleery told the Inquirer.