Very few painkillers are safe to use during pregnancy, and yet one of the only available options has become embroiled in an international debate in recent years.
Acetaminophen, also known as paracetamol, is generally considered to be the safest painkiller to use during pregnancy, and yet emerging research that has linked the drug to attention deficit hyperactivity disorder ( ADHD) suggests there may be overlooked risks to early brain development.
In a small new study, researchers in the US tracked bloodstream levels of acetaminophen in 307 Black women during their pregnancy. They found those who used acetaminophen later gave birth to children more than three times as likely to receive an ADHD diagnosis.
For daughters, exposure to acetaminophen in the womb was linked to a more than six-fold increase in the risk of ADHD within the first ten years of life.
While that sounds concerning on the surface, these initial results are not conclusive and should not scare off the large percentage of people who rely on acetaminophen during pregnancy for pain or fever. Especially since robust evidence shows both of those symptoms can be threats to a developing fetus if left untreated.
As with any medicine, the benefits of acetaminophen must be balanced by the risks. Unlike its pros, however, the long-term cons are not as well researched.
“This medication was… approved decades ago, and may need reevaluation by the FDA,” argues pediatrician Sheela Sathyanarayana from UW Medicine.
“Acetaminophen was never evaluated for fetal exposures in relation to long-term neurodevelopmental impacts.”
In recent years, several other epidemiology studies have found associations between acetaminophen use during pregnancy and ADHD outcomes in children, and yet some studies have produced conflicting results. All of these investigations are purely correlational and their findings are not a cause for alarm, some scientists argue, but rather, alertness.
Nevertheless, lead author Brennan Baker, from Seattle Children’s Research Institute, thinks it may be time for the FDA to take another look at acetaminophen’s safety during pregnancy.
The last time the FDA did so was in 2015, when officials declared there was inconclusive evidence to connect acetaminophen use in pregnancy and ADHD in children.
“[Acetaminophen] is an important medication and alternatives for treatment of high fever and severe pain are limited,” they wrote in a Consensus Statement for Nature Reviews Endocrinology in 2021.
In response to the 2021 commentary, officials at ACOG held firm.
“Neurodevelopmental disorders, in particular, are multifactorial and very difficult to associate with a singular cause. The brain does not stop developing until at least 15 months of age, which leaves room for children to be exposed to a number of factors that could potentially lead to these issues,” they wrote in 2021.
“The conflicting results means that more research is needed,” says Baker.
The study was published in Nature Mental Health.