Can Factors During Pregnancy and Birth Predict ADHD Symptoms in Children?

What you need to know

• Information known at birth, like sex and pregnancy complications, can predict about 8% of ADHD symptoms in 9-10 year old children
• The predictive ability of prenatal factors varies across different groups, being stronger for low-income families and children with family history of mental health issues
• Several potentially preventable factors during pregnancy were linked to higher ADHD symptoms, like maternal substance use and certain health complications

Predicting ADHD symptoms from early life factors

Attention-deficit/hyperactivity disorder (ADHD) is a common neurodevelopmental condition that affects many children. Researchers have long been interested in understanding what factors during pregnancy and around the time of birth might influence a child’s risk of developing ADHD symptoms later on. This study looked at data from nearly 10,000 children in the United States to see how well information available at birth could predict ADHD symptoms when the children were 9-10 years old.

The researchers found that factors known at birth could explain about 8% of the differences in ADHD symptoms between children. While this may seem like a small amount, it suggests that events very early in life do play a role in shaping later ADHD risk, even if they don’t tell the whole story.

Some of the key factors that predicted higher ADHD symptoms included:

• Being male
• Mother using drugs or smoking during pregnancy
• Having more pregnancy or delivery complications
• Mother having anemia or urinary tract infections during pregnancy
• Younger parental age

Interestingly, factors that are often thought to be important, like low birth weight, did not end up being strong predictors when considering all these other factors together.

Group differences in predictability

An important finding was that prenatal factors were not equally predictive for all children. The ability to predict ADHD symptoms from early life information varied quite a bit for different groups:

• For children from low-income families, early factors explained about 10% of ADHD symptoms, compared to only 3% for high-income families. This suggests children in low-income settings may be more vulnerable to prenatal risks.

• Prediction was more accurate for White children compared to Black or Hispanic children. The reasons for this are unclear but could relate to differences in healthcare access or experiences of discrimination.

• Early factors were more predictive for children whose parents had mental health issues themselves. This may reflect a combination of genetic and environmental influences.

• While being male was a strong predictor overall, certain factors like delivery complications seemed to matter more for boys than girls in predicting later ADHD symptoms.

These group differences highlight that the link between prenatal experiences and ADHD risk is complex and can vary based on a child’s broader life circumstances.

Potentially modifiable risk factors

Some of the prenatal factors linked to higher ADHD symptoms are potentially preventable or treatable. For example:

• Maternal substance use during pregnancy, including smoking and drug use, was associated with increased ADHD symptoms. This underscores the importance of supporting pregnant women to avoid harmful substances.

• Urinary tract infections and anemia during pregnancy were linked to higher ADHD symptoms. Improved screening and treatment for these conditions could potentially reduce risk.

• The total number of pregnancy complications mattered, suggesting that overall maternal health during pregnancy is important.

• Younger parental age was associated with higher ADHD symptoms, highlighting a potential benefit of delaying parenthood for some.

While we can’t say these factors directly cause ADHD, addressing them could potentially help reduce risk for some children.

Limitations and future directions

It’s important to note some key limitations of this study:

• The information about pregnancy and birth was reported by parents when children were 9-10 years old, so there may be some inaccuracies in recall.

• The study only explains a small portion of the differences in ADHD symptoms between children. Many other factors not measured here, including genetics, likely play important roles.

• This study looked at ADHD symptoms on a scale, not diagnosed ADHD. The findings may be somewhat different for clinical ADHD diagnoses.

Future research should aim to replicate these findings using medical records from pregnancy and birth, rather than relying on parent recall. It would also be valuable to combine this early life information with other known risk factors for ADHD to develop more comprehensive prediction models.

Additionally, more work is needed to understand why prenatal factors seem to matter more for some groups than others. This could help target prevention efforts to those most likely to benefit.

Conclusions

• Events during pregnancy and around birth play a role in shaping later ADHD risk, but explain only a small portion of the differences between children
• The impact of early life factors on ADHD symptoms varies across different groups in the population
• Some potentially modifiable factors during pregnancy, like maternal health issues and substance use, are linked to higher ADHD symptoms
• More research is needed to develop comprehensive early prediction models for ADHD that could guide prevention efforts