FILED IN: Health

Environmental factors for autism: Low oxygen during delivery, summer births

Hypoxia and other complications during birth can contribute to the development of ASD

A recent study published in the medical journal Pediatrics revealed that certain complications during childbirth may put children at an increased risk of developing autism.

The study was the first of its kind in regards to autism. Researchers from Harvard and Brown analyzed the data from 64 previous studies relating to perinatal (birth) and neonatal (post-birth) risk factors for the disorder.

Babies whose oxygen supply is interrupted during birth are at greater risk of developing autism, according to a Harvard/Brown study. Photo via Wikipedia Commons.

The data from the previous studies ranged from factors such as low birth weight and apgar scores, prolonged, induced and early labor, cesarean and breech births, even the time of year the child was born. Other variables such as forceps delivery, jaundice and discolored amniotic fluid were also examined.

The recent study concluded that, of all the factors that were studied in the past, there are several events that can be associated with an increased risk of autism. They include: having the umbilical cord around baby’s neck, meconium entering the lungs, abnormal fetal presentation or breech delivery, fetal respiratory distress, birth injury or trauma, low 5-minute APGAR score, newborn seizures, low birth weight, multiple births, low blood iron and being born in the summer.

What captured the researchers attention was that many of these risk factors involve decreased blood flow to the brain. Also known as Hypoxia, the disruption of oxygen to the brain can lead to increased dopamine levels. Elevated levels are typically found in those who have been diagnosed with autism.

One theory is, that when combined with a genetic predisposition, oxygen deprivation to the brain can have a detrimental effect on development. The findings are significant to not only autism but other genetic mental disorders such as schizophrenia, attention deficit and obsessive-compulsive disorders.

Also of significance, researchers found that babies born in the months of March and August had an elevated occurrence of autism in 6 out of 12 studies. Of the seasons, summer births had an higher incidence. Reasons for the relationship are unclear, however researchers thought this could be from variation in viral or other infections, nutritional factors or vitamin deficiencies.

While the study doesn’t determine if a child will develop autism, it does provide insight into the disorder. Parents and doctors of at risk children can look out for early signs of the disease and take action sooner if symptoms arise.