Ever wonder what causes Attention Deficit Hyperactivity Syndrome (ADHD) in kids? A new study in the Journal of The American Medical Association  found babies born just one month premature are more likely to develop ADHD. The study compared pre-term deliveries to siblings that were born at full term. Experts say that eliminates genes that the fetus has and parenting styles after the baby is born, allowing people to truly tell how much is related to pre-term deliveries. Researchers analyzed 113,000 children and measured the children’s levels of ADHD symptoms from pre-school age to 8 years old. They found that infants born at less than 34 weeks were at a greater risk of developing symptoms of ADHD. For unclear reasons, the results are particularly true of girls.

In the video, Dr. Angela Martin, an OB-GYN with The University of Kansas Health System, says somewhere between five and 10 percent of kids in the United States have ADHD. She says researchers are finding it’s caused by a number of different factors, and pre-term birth is one that increases the risk. She says, unfortunately, there is no guaranteed method for preventing premature births. But, Dr. Martin has advice on how mothers can reduce the risk.

The video also shows file video of premature babies in the neonatal intensive care unit.