Babies exposed to low levels of oxygen in the womb have higher chances of developing attention deficit hyperactivity disorder (ADHD), says a new study.

Researchers from Kaiser Permanente looked at the effects of ischemic-hypoxic conditions (IHC), situations when the brain is deprived of oxygen, on development of babies.

The study involved 82,000 5-year-old children. Researchers found that prenatal exposure to IHC - especially birth asphyxia, neonatal respiratory distress syndrome, and preeclampsia - increased the risk of babies being diagnosed with ADHD by 16 percent.

Researchers found that preeclampsia increased the risk of the baby developing ADHD by almost 35 percent. Preeclampsia is a condition where a pregnant woman develops high blood pressure and has more protein in the urine during the last stages of pregnancy.

Neonatal respiratory distress syndrome was associated with a 47 percent greater risk of ADHD. This condition is common in premature babies who find it difficult to breathe as their lungs aren't fully developed.

Birth asphyxia increased the risk of ADHD by 26 percent. Birth asphyxia is when the baby doesn't receive enough oxygen either before, during or after birth.

"Previous studies have found that hypoxic injury during fetal development leads to significant structural and functional brain injuries in the offspring. However, this study suggests that the adverse effect of hypoxia and ischemia on prenatal brain development may lead to functional problems, including ADHD," said Darios Getahun, MD, lead author of the study, from the Kaiser Permanente Southern California Department of Research & Evaluation.

Apart from conditions that lead to low levels of oxygen, deliveries that were breech, transverse (shoulder-first) or had complications associated with the cord were found to be associated with a 13 percent increased risk of ADHD, according to a news release.

"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. We suggest future research to focus on pre- and post-natal conditions and the associations with adverse outcomes, such as ADHD," said Getahun.