Growing evidence notes that stress and distress – which occurs when stress is prolonged, severe or both – during pregnancy is linked to offspring risk for externalizing behavior outcomes, such as reactive/aggressive behaviors, hyperactivity and impulsivity, among others.

A new study published by the American Psychological Association in the journal APA PsycNET suggested that psychological stress and distress during the pregnancy period uniquely increases the odds of "children developing and exhibiting aggressive, disinhibited and impulsive behaviors." Researchers noted that while effects may be relatively small, they may persist across developmental periods from early childhood through adolescence.