The use of common painkiller acetaminophen (APAP), also known as paracetamol and often sold as Tylenol, during pregnancy is linked to an increased risk of developmental disorders. A consensus of 91 clinicians and researchers, published in Nature Reviews Endocrinology, is now calling for caution and additional research.
APAP is the active ingredient in over 600 medications used to treat mild to moderate pain and fever. The drug is available over the counter and is widely used by pregnant women. A new review based on 25 years of research suggests that pregnant women should not use APAP unless medically indicated and that they should use the lowest effective dose for the shortest possible time.
In their review, the researchers highlight that APAP is known to cross the placenta and the blood-brain barrier. They add that pregnancy may cause changes in APAP metabolism, potentially making fetuses more vulnerable to toxic effects. Other studies have found that APAP inhibits prostaglandin signaling in the third trimester, which may lead to ductus arteriosus constriction and life-threatening cardiac failure in babies.
“In vivo, in vitro and ex vivo studies have shown that APAP directly perturbs hormone-dependent processes, including inhibition of androgen production and increased estrogen production, disruption of steroidogenesis, depletion of sulfated sex hormones, perturbation of immune function, induction of oxidative stress and indirect activation of the endocannabinoid system,” wrote the researchers.
The researchers made note of other studies finding that APAP exposure in the womb is linked to male urogenital and reproductive tract abnormalities, such as undescended testicles and reduced anogenital distance, and early female puberty.
They also mentioned that neurodevelopmental effects linked to prenatal APAP exposure include ADHD, autism, language delays, decreased IQ, cerebral palsy, oppositional-defiant disorder, decreased executive function, and conduct disorders.
“The current near-ubiquitous use of acetaminophen during pregnancy is due in part to the widespread perception – even among doctors – that it has limited side effects and negligible risk,” said Ann Z. Bauer, lead author of the review in an article published in The Conversation.
“But a growing body of research suggests that the indiscriminate use of acetaminophen during pregnancy – especially for conditions such as chronic pain, low back pain, and headaches – may be unwarranted and unsafe,” she added.
“In our consensus statement, we urge education of health professionals and pregnant women about the risks and benefits of acetaminophen use during pregnancy,” she explained.