What is the likelihood of an infant developing neurodivergence after using Tylenol (Acetaminophen)?

From the Guidelines

There is a significant association between prenatal acetaminophen exposure and an increased risk of neurodevelopmental disorders, including ADHD and ASD, in children.

Key Findings

• A comprehensive review of existing evidence suggests that prenatal exposure to acetaminophen may contribute to child neurodevelopment outcomes, including ADHD and ASD 1.
• The review found positive associations between maternal prenatal acetaminophen use and ADHD outcomes in 26 out of 29 studies, with a potential dose-dependent relationship 1.
• Another study found that prenatal acetaminophen exposure was associated with an increased risk of ADHD outcomes, with a risk ratio range of 1.08-1.34 1.
• A narrative synthesis of included reviews found consistent associations between prenatal acetaminophen exposure and increased risk of ADHD outcomes, with a potential dose-dependent relationship 1.
• The risk ratios for ADHD outcomes ranged from 1.08 to 1.34, with some studies suggesting a stronger association for males than females 1.
• A study based on data from the Danish National Birth Cohort found that any prenatal use of acetaminophen was associated with an increased risk for ASD with a hyperkinetic disorder, with a hazard ratio of 1.51 (95% CI, 1.19-1.92) 1.

Mechanisms

• The exact mechanisms underlying the association between prenatal acetaminophen exposure and neurodevelopmental disorders are not fully understood, but may involve the activation of the maternal immune system and fetal endocannabinoid system 1.
• Animal studies have found links between exposure to acetaminophen and lower levels of brain-derived neurotrophic factor (BDNF) in the striatum, with alterations in the metabolism of dopamine identified as well 1.

Clinical Implications

• The findings of these studies suggest that minimization of prenatal acetaminophen exposure may be necessary to reduce the risk of ADHD outcomes in children 1.
• Clinicians should be aware of the potential risks associated with prenatal acetaminophen exposure and consider alternative pain management options for pregnant women 1.

From the Research

Neurodivergence and Tylenol (Acetaminophen) Use

The likelihood of an infant developing neurodivergence after using Tylenol (Acetaminophen) is a topic of ongoing research and debate. Several studies have investigated the potential link between acetaminophen use and neurodevelopmental disorders, including autism spectrum disorder (ASD), attention-deficit/hyperactivity disorder (ADHD), and intellectual disability.

Key Findings

• A systematic review of 218 papers on the safety of paracetamol (acetaminophen) use in infants and children found that none of the studies monitored neurodevelopment, and the median follow-up time was only 48 hours 2.
• A study published in 2023 concluded that exposure to acetaminophen (paracetamol) in susceptible babies and children may induce many cases of ASD, and that the very early postpartum period poses the greatest risk for acetaminophen-induced ASD 3.
• A nationwide cohort study of 2,480,797 children born in Sweden between 1995 and 2019 found no association between acetaminophen use during pregnancy and children's risk of autism, ADHD, or intellectual disability in sibling control analysis 4.
• A systematic review of 16 high-quality papers found an association between acetaminophen use and adverse neurodevelopmental outcomes, including ASD, ADHD, and intellectual disability 5.
• A narrative review of direct and indirect evidence on the safety of pediatric use of paracetamol (acetaminophen) concluded that prenatal exposure to paracetamol causes statistically significant risks of developmental delays, ADHD, and a subtype of ASD associated with hyperkinetic behavior 6.

Potential Risks and Associations

• The use of acetaminophen during pregnancy and early childhood may be associated with an increased risk of neurodevelopmental disorders, including ASD, ADHD, and intellectual disability.
• The very early postpartum period may pose the greatest risk for acetaminophen-induced ASD.
• Oxidative stress may put some babies and children at risk of paracetamol-induced neurodevelopmental injury.
• Long-term use, increased dose, and frequency of acetaminophen may be associated with a stronger association with adverse neurodevelopmental outcomes.