Acetaminophen has been accumulating some evidence against its routine use in recent years, and now there may be more: The drug, if used during pregnancy, may raise the risk of behavior problems in the children years later. The authors of the new study, out in the journal JAMA Pediatrics, say it’s too early to make any new recommendations for the public just yet. But since the results do suggest that prenatal use may as much as double the risk of behavior disorders in the child, pregnant women may want to take the study into consideration, or talk with their doctors.
The study followed over 64,000 families in the Danish National Birth Cohort. The mothers filled out questionnaires regarding the frequency of their acetaminophen use during pregnancy, and answered questions about various aspects of their children’s behavior. Official diagnoses of hyperkinetic disorder (HKD), a severe form of ADHD, were tracked, as well as the number of prescriptions for ADHD medications (e.g. Ritalin).
Just over half the women taking part in the study used acetaminophen during pregnancy.
Use of the drug was strongly linked to increased risk for ADHD in the children in the first seven years of life, an increase of as much as 30%. Acetaminophen was also linked to a 37% greater risk for having an HKD diagnosis. And the more often the pregnant mothers used the drug, the higher their children’s risk of behavioral problems.
“When women reported having used acetaminophen for 20 or more weeks during pregnancy, the risk for HKD diagnosis in children almost doubled,” the authors write. And the odds of the children being prescribed an ADHD medication rose by 50%.
The results held up even when factors like maternal mental health, inflammation, and infection during pregnancy were accounted for.
Acetaminophen can cross the placenta, making its way to the fetus and its delicate developing nervous system. The drug is a known endocrine (hormone) disrupter, and has previously been linked to undescended testes in male infants. Since the maternal hormone environment plays a critical role in the development of the fetus, the authors say that it’s “possible that acetaminophen may interrupt brain development by interfering with maternal hormones or via neurotoxicity such as the induction of oxidative stress that can cause neuronal death.”
All this said, causation can’t be determined from the current study – there is only a correlation between a mother’s acetaminophen use and behavioral/attention problems in the child. So there could be another factor or multiple factors at play, which haven’t been teased apart yet. For this reason, the authors say that it’s too early to make any specific recommendations for pregnant women.
But, they add, if causation could be demonstrated, then “acetaminophen should no longer be considered a safe drug for use in pregnancy.”
The authors of an accompanying editorial also point out that the results “underline the importance of not taking a drug’s safety during pregnancy for granted.” More research, they urge, will certainly be needed to address the remaining questions.
In the meantime, if you’re concerned, it may be wise to cut down on acetaminophen if you’re pregnant – it certainly shouldn’t be used routinely or for long periods. But talk with your doctor if you have questions about this, or any medications, you’re taking.