The risk that a child will have Attention Deficit Hyperactivity Disorder (ADHD) is relatively low among the general population. However, a new study suggests that the more premature a baby is when born; the risk for ADHD increases significantly.
Finnish researchers led by Dr. Minna Sucksdorff of the University of Turku compared more than 10,000 children with ADHD against more than 38,000 children without ADHD but similar in terms of gender, birth date and place of birth.
The researchers used birth medical records to see how far along in the pregnancy the mother was when the child was born. They also looked at whether the children were underweight or overweight for what is expected at that gestational age.
The study results showed that the risk of ADHD increased for each week earlier that a child was born. A full-term pregnancy is considered to be 40 weeks.
The odds of children with ADHD were 10 times greater when they were born during the 23rd to 24th week of pregnancy. Children born between the 27th and 33rd week of pregnancy were twice as likely to have ADHD compared to those without ADHD.
Other factors that affect gestational age and ADHD were also taken in account such as the mother’s age and whether she smoked or used drugs or alcohol. After these considerations, the findings remained the same.
In regards to birth weight, researchers found that infants born at very low or very high weight percentages were also at a higher risk for ADHD.
These findings imply that the pathways in the fetal brain may develop differently in children who are not adequately nourished, or are over-nourished, in the womb, or once a child is delivered prematurely, said Dr. Glen Elliott, chief psychiatrist and medical director of Children's Health Council in Palo Alto, Calif.
However, he added, this type of study cannot show that premature birth or growth rate in the womb actually causes ADHD. Symptoms of the common brain disorder include inattention, impulsive behavior and hyperactivity, which can affect a child's ability to learn and make friends.
Most early cesarean births happen because a mother and / or her infant are in distress and surgery is needed to protect one or the other or both of their health. Planned cesareans are typically scheduled close to the original due date and are unlikely to be associated to ADHD risk. However, the findings may give doctors something to consider when making a decision about cesarean birth.
"Since both gestational weight and gestational age have marked effects, clinicians may face difficult choices if a fetus is not thriving in the womb at an early gestational age," Elliott said. "Does one deliver the child early to enhance nutrition or delay to minimize the effects of premature delivery?"
The risk is still low overall that a child will have ADHD, and these findings are based on a child's relative risk of having the condition compared to others, Elliott added. The study suggests that the chance for ADHD appears to be greatest among the very premature babies.
The findings were published in the August 24th online edition of the journal Pediatrics.
Source: Tara Haelle, http://www.webmd.com/baby/news/20150824/adhd-risk-rises-for-each-week-a-preemie-is-born-early