(HealthDay News) — Risks of attention-deficit/ hyperactivity disorder (ADHD) are greatest for children with the most severe degree of poor growth in the womb, according to research published online August 24 in Pediatrics.
Minna Sucksdorff, MD, of the University of Turku in Finland, and colleagues compared 10,321 children with ADHD against 38,355 children without ADHD but similar in terms of gender, birth date, and place of birth. The authors used medical records to identify gestational age at birth. They also looked at whether the infants were underweight or overweight for what is expected at that gestational age.
The researchers found that the risk of ADHD increased for each week earlier that a child was born. The children with ADHD had more than 10 times greater odds of being born at 23 or 24 weeks of pregnancy than the children without ADHD. And children with ADHD were at least twice as likely to be born between 27–33 weeks, compared to those without ADHD. This finding remained after the researchers took into account other factors that affect gestational age and ADHD risk, such as the mother’s age and whether she smoked or used drugs or alcohol. The researchers also found increased risk when weight for gestational age was 1 SD below and 2 SD above the mean.
“This highlights the importance of taking into account both prematurity and poor fetal growth when planning the timing of birth as well as later follow-up and support policies,” the authors write.