Pregnancy risks for ADHD in kids

One of the largest population studies of Attention Deficit/Hyperactivity Disorder (ADHD) in children has revealed maternal smoking during pregnancy to be an important risk factor.

The research was conducted at Perth's The Kids for Child Health Research and published in the prestigious international journal Pediatrics.

The study of 12,991 West Australian children diagnosed with ADHD found that, compared with mothers whose children did not have ADHD, mothers of children with ADHD were significantly more likely to be younger, single, smoked in pregnancy, had some complications of pregnancy and labour and were more likely to have given birth slightly earlier. It did not make any difference if the child was a girl or a boy.

ADHD is the most common neurodevelopment disorder affecting 5.2% of children worldwide with well-known clinical consequences and functional outcomes that can affect individuals throughout their lifespan.

Lead author Dr Desiree Silva said there is a strong genetic predisposition to ADHD, as well as some evidence of early environmental and maternal factors playing a part.

"Ours is one of the largest population-based studies to date, and uses a careful clinical definition of ADHD and links a range of data sets, which overcome many of the limitations of previous studies," said Dr Silva.

"We found that certain maternal factors did increase the risk of ADHD in the child with smoking during pregnancy being a significant risk factor.

"Other factors such as low birth weight, giving birth at greater than full term, and low Apgar scores in the baby were not associated with an increased risk of ADHD in the child."

Dr Silva said smoking in pregnancy is an important risk factor for many health outcomes for the mother and the baby and women should be encouraged not to smoke during pregnancy.

"It's important that mothers recognise the risk of ADHD associated with smoking in pregnancy and take steps to reduce that risk," she said.

"Attention to maternal infections and pre-eclampsia may also reduce this risk of ADHD."

Dr Silva cautioned that the study had identified broad risk factors rather than causes and that the information could not be used to identify the factors associated with any particular child's disorder.

She said further studies are needed to better understand the genetic and environmental risk factors of ADHD.

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