Taking acetaminophen, commonly known as Tylenol, while pregnant does not increase a child’s risk of autism, ADHD, or intellectual disability. The corresponding systematic review and meta-analysis was published in The Lancet Obstetrics, Gynaecology.
"Our findings suggest that previously reported links are likely to be explained by genetic predisposition or other maternal factors such as fever or underlying pain, rather than a direct effect of the paracetamol itself,” said lead author Asma Khalil, Professor of Obstetrics and Maternal Fetal Medicine at City St George's, University of London, in a press release.
Researchers analyzed 43 studies in their systematic review and 17 in their meta-analysis. In particular, they compared pregnancies in which acetaminophen was used or not used, paying special attention to studies wherein one sibling was exposed to acetaminophen during pregnancy while another born to the same mother was not. The researchers analyzed data for almost 263,000 children assessed for autism, over 335,000 assessed for ADHD, and over 406,000 evaluated for intellectual disability.
Ultimately, they found no evidence that acetaminophen use during pregnancy increased risk of any of these conditions when compared to pregnancies wherein the medications were not used. The findings were consistent across studies with a low risk of bias and those with follow-up periods exceeding five years.
“The message is clear- paracetamol remains a safe option during pregnancy when taken as guided. This is important as paracetamol is the first-line medication we recommend for pregnant women in pain or with a fever, and so they should feel reassured that they still have a safe option to relieve them of their symptoms,” said Khalil.
In their study, the researchers wrote that acetaminophen is typically used intermittently and that its prolonged use raises questions about whether the underlying conditions promoting its extended use may be more critical for shaping neurodevelopment than the drug itself. They noted that future research should prioritize dose-response analyses, trimester-specific exposure, and an integration of mechanistic and epidemiological approaches.