"This study does not present new experimental findings; rather, it synthesises and critiques the existing evidence. Its central focus is whether paracetamol (also known as acetaminophen) taken during pregnancy is associated with adverse outcomes in children, particularly attention deficit hyperactivity disorder (ADHD) and autism spectrum disorder (ASD).

Most of the studies considered in the review are retrospective in design — meaning they examine events after they have occurred. Such studies can highlight associations but cannot prove cause and effect. For example, one common reason pregnant women take paracetamol is to reduce fever. If later analyses show their children have higher rates of developmental difficulties, it is difficult to determine whether the medication itself was responsible or whether the fever contributed to the outcome. Retrospective research is also prone to biases — such as recall bias, publication bias and selection bias — that may distort results. Statistical methods can reduce these issues, but they cannot fully eliminate them.

What, then, can be inferred? The balance of evidence indicates that prolonged or high-dose use of paracetamol during pregnancy may carry risks for the child, whereas occasional or short-term use is unlikely to be harmful. This conclusion aligns with a broader principle in medicine: all medications should be used cautiously, only when clearly necessary, at the lowest effective dose, and for the shortest possible time. This guidance is particularly important in pregnancy, when many alternatives to paracetamol for pain and fever management have well-established risks that are considerably greater.

Research shows that both autism spectrum disorder (ASD) and attention-deficit/hyperactivity disorder (ADHD) are predominantly driven by genetic factors, which account for around 70–80% of overall risk, while environmental influences together contribute only about 20–30%. Among these environmental factors, many influences are involved — such as parental age, prematurity, maternal health conditions, and air pollution — each contributing only modestly. Any effect of paracetamol use in pregnancy is therefore likely to be very small relative to these much larger genetic influences. This means that even if paracetamol was completely eliminated during pregnancy, it would almost certainly have only a negligible impact on the overall prevalence of ADHD and ASD at the population level."

"Evidence is mixed. A recent review in the US has reported associations between prenatal paracetamol use and slightly higher rates of autism, but a large Swedish study using sibling comparisons had found no effect when family factors were controlled. The observational studies in the US review differ in design (e.g. self-report vs prescription data), exposure timing and duration, and how other confounders were adjusted - therefore, the results of this study have to be taken with caution.

Outcome data are inconclusive due to study limitations, and causal associations have not been established from the literature. Benefits vs risk of foetal harm from medical condition (e.g. maternal fever and pain) versus the use of paracetamol in pregnancy should be weighed by the healthcare team.

If paracetamol is taken, it is recommended to take the lowest effective dose for the shortest duration under medical guidance. Pregnant women should discuss any persistent or recurrent symptoms with their healthcare team."

"Autism is a neurodevelopmental condition with no known single cause. However, research shows that genetics play a large role, with hundreds of genes being linked to autism. Recent suggestions that Tylenol use during pregnancy could increase the risk of autism has understandably raised concern among expectant parents.

However, no study has shown that acetaminophen, the main ingredient in Tylenol, causes autism. Some studies have reported an association between acetaminophen use and autism, while others have not. Importantly, association does not mean causation.

A recent large-scale study, which analysed data from 2.48 million births, found that when researchers compared siblings (a method to control for genetic and environmental factors) any apparent links between acetaminophen and autism disappeared. This suggests that other factors such as genetic or underlying maternal health conditions may better explain the findings.

It's also worth noting that fever itself has been linked to adverse pregnancy outcomes. In many cases treating a fever with acetaminophen may reduce those risks. Pregnant people should continue to follow the advice of their healthcare providers when managing pain and fever."

"There has been research exploring whether taking acetaminophen (also called paracetamol) during pregnancy could increase the likelihood of the offspring of the pregnancy being diagnosed with autism. Some studies have reported small associations, but these findings are not consistent and do not prove that acetaminophen directly causes autism.

Autism is a complex condition influenced by many genetic and environmental factors. Any small associations in this area need to be weighed against the risk of untreated high fever in pregnancy for the woman and the developing baby."