Updated 13 June 2017

Near-term babies still have higher risk of ADHD

Very premature babies are known to be at a greater risk of developing ADHD but now, new research suggests that babies born even a week or two shy of their scheduled date could also have an elevated risk.

"There has been quite a lot of research on very pre-term birth and the increased risk for ADHD but less evidence when it comes to late pre-term birth (weeks 34-36) and even less regarding babies born early term (weeks 37-38)," said lead author Dr. Minna Sucksdorff of the University of Turku in Finland.

In premature babies, the brain is still developing, and whatever caused the premature birth, like an infection in the mother, may have affected the brain, Sucksdorff told Reuters Health by email.

Researchers used three Finnish health registries to identify 10,321 children diagnosed with ADHD who had been born between 1991 and 2005. They compared each child with ADHD to four children without ADHD who had a similar birth date, gender and place of birth.

The registries included data on gestational age at birth, which was calculated using the mother's last menstrual period and first trimester ultrasound. Forty weeks is considered "full term."

Based on standards for each week of gestational age, the researchers noted which babies had been born of average weight, smaller than average or larger than average.

Mother's lifestyle plays an important role

Mother's age, substance abuse and smoking during pregnancy, number of previous births, marital status, father's age, and the urbanity of the child's birthplace were associated with gestational age, birth weight and ADHD, the authors reported in Pediatrics.

Accounting for other factors, premature birth was still associated with ADHD, with the risk increasing steadily as gestational age decreased.

Babies born at 25 weeks of gestational age were more than five times, or 500 percent, more likely to be diagnosed with ADHD as those born at 40 weeks.

At 38 weeks, babies were about 12 percent more likely to develop ADHD than those born full term.

Infants born significantly small or large for their gestational age also had an increased risk of ADHD.

This is not surprising, said Guilherme Polanczyk of the University of Sao Paulo Medical School in Brazil, as there is good evidence showing that prematurity and poor fetal growth are associated with a variety of chronic disorders such as high blood pressure, cardiovascular disease, diabetes, and mental disorders, including ADHD.

The fact that even some early term babies, who would not be considered premature, had an increased risk may indicate that the risk is continuous, with no specific cut-off point, he said by email.

"It is very interesting that those big for gestational age also have an increased risk," he said. "This is consistent with a large body of evidence showing that deviations of brain development may also occur in this population, probably because of different disease mechanisms."

Polanczyk was not part of the Finnish study.

"It is more and more established that prenatal health is very important also for mental, emotional, and cognitive development," Polanczyk added. "Preventing preterm birth is always an important goal, because it has a causal role to a variety of other negative outcomes."

Identifying children with increased ADHD risk may improve early detection and intervention, which can help reduce the adverse outcomes of ADHD, he said.

According to Sucksdorff, about five percent of children worldwide are diagnosed with ADHD.

Read more:

Premature babies at risk of ADHD

Painkiller use during pregnancy tied to ADHD in kids


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Dr Renata Schoeman has been in full-time private practice as a general psychiatrist (child, adolescent and adult psychiatry) since 2008, currently based in Oude Westhof (Bellville). Renata also holds appointments as senior lecturer in Leadership (USB) and as a virtual faculty member of USB Executive Development’s Neuroleadership programme. She serves on the advisory boards of various pharmaceutical companies, as a director of the Psychiatric Management Group (PsychMG) and is the co-convenor of the South African Society of Psychiatrist (SASOP) special interest group for adult ADHD, and co-founder of the Goldilocks and The Bear Foundation ( She is passionate about corporate mental health awareness and uses her neuroscience background to assist leaders in equipping them to become balanced, healthy and dynamic leaders that take their own and their team’s emotional, intellectual, social health and physical needs into account. Renata is academically active and enjoys research and collaborative work, has published in many peer-reviewed journals, and has presented at local and international congresses. She is regularly invited to present at conferences and to engage with the media. During her post-graduate studies, she trained at Harvard, Boston in neurocognition and neuroimaging. Her awards include, amongst others, the Young Minds in Psychiatry award from the American Psychiatric Association, the Discovery Foundation Fellowship award, a Thuthuka award from the NRF, and a MRC Fellowship. She also received the Top MBA student award and the Director’s award from USB for 2015. She was a finalist for the Businesswomen’s Association of South Africa’s Businesswoman of the Year Award for 2016, and received the Excellence in Media Work award from SASOP during 2016.

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