A new study discovers a difficult pregnancy and childbirth that limit the amount of oxygen to the brain of a fetus or infant may lead to attention deficit hyperactivity disorder (ADHD). Historically, ADHD has been linked to familial and genetic influences.
Kaiser-Permanente researchers performed a population-based study that examined the association between conditions that result in neonatal low oxygen and ADHD.
Researchers examined the electronic health records of nearly 82,000 children ages 5 years old and found that prenatal exposure to ischemic-hypoxic conditions — especially birth asphyxia, neonatal respiratory distress syndrome, and preeclampsia — was associated with a 16 percent greater risk of developing ADHD.
Specifically, exposure to birth asphyxia was associated with a 26 percent greater risk of developing ADHD, exposure to neonatal respiratory distress syndrome was associated with a 47 percent greater risk, and exposure to preeclampsia (high blood pressure during pregnancy) was associated with a 34 percent greater risk.
The study also found that the increased risk of ADHD remained the same across all race and ethnicity groups.
“Previous studies have found that hypoxic injury during fetal development leads to significant structural and functional brain injuries in the offspring,” said study lead author Darios Getahun, M.D., Ph.D. “However, this study suggests that the adverse effect of hypoxia and ischemia on prenatal brain development may lead to functional problems, including ADHD.”
Researchers also found that the association between IHC and ADHD was strongest in preterm births and that deliveries that were breech, transverse (shoulder-first) or had cord complications were found to be associated with a 13 percent increased risk of ADHD.
These associations were found to be the case even after controlling for gestational age and other potential risk factors.
“Our findings could have important clinical implications. They could help physicians identify newborns at risk that could benefit from surveillance and early diagnosis, when treatment is more effective,” said Getahun.
“We suggest future research to focus on pre- and postnatal conditions and the associations with adverse outcomes, such as ADHD.”
During critical periods of fetal organ development, hypoxia and ischemia may result in a lack of oxygen and nutrient transport from the mother’s blood to fetal circulation. This may lead to compromised oxygen delivery to tissues and cerebrovascular complications.
This study suggests that the adverse effect of hypoxia on prenatal brain development may lead to also lead to functional problems, including ADHD.
In 2005, the Centers for Disease Control and Prevention estimated the annual cost of ADHD-related illness in children under 18 years of age to be between $36 billion and $52.4 billion, making the condition a public health priority.
ADHD is estimated to affect approximately 8.4 percent of children ages 3 to 17. ADHD persists into adulthood for about half of these children. Symptoms of ADHD in children may include attention problems, acting without thinking, or an overly active temperament.
The study is published in the journal Pediatrics.
Source: Kaiser Permanente