Each unit increase in omega-6:omega-3 ratio from umbilical cord plasma was linked to a 13% higher risk of ADHD symptoms at 7 years old.
This study also found that a high prenatal n-6:n-3 ratio concentration in the cord plasma is associated with ADHD symptoms during childhood and this association may be driven by low DHA concentrations. DHA is an omega-3 fatty acid that makes up ~30% of the lipids found in the brain.
This study was an observational study which means causation cannot be established even though the data was still significant after adjusting for many confounding factors including maternal education, socioeconomic status and more.
These results are in line with randomized controlled trials showing prenatal DHA supplementation improves attention at age 5.