Researchers from Duke University found that pregnant women whose labors are induced have a higher chance of giving birth to babies with autism, especially if the baby is a boy.
Induced and augmented labor has become very common these days. Induced labor is the act of stimulating contractions before the onset of spontaneous labor and augmented labor is increasing the strength, duration or frequency of contractions during labor. According to the most recent numbers available from the National Vital Statistics Reports, in 2010, 23.4 per cent of deliveries were induced, an increase from 9.5 per cent in the early 1990s. Data from 2002, the most recent available, shows 17.3 per cent of deliveries were augmented that year; as opposed to only 10.9 per cent in 1989. Both these forms of labor are known to prevent complications, including stillbirth.
However, in a study published in JAMA Pediatrics on Aug. 12, 2013, researchers found that induced or augmented labor increases the risk of autism in a newborns, especially in boys.
"Inducing or augmenting labor has been previously suggested as a contributing factor to autism development," said lead author Simon G. Gregory, PhD, associate professor of medicine and medical genetics at Duke in a press release. "However, these studies produced conflicting results and consisted of a relatively small number of subjects. Our study is by far the largest one of its kind to look at the association between autism and induction or augmentation."
The study didn't confirm any causes or effects of this increased risk of autism and researchers suggested further studies need to be conducted on the subject.
For the new study, researchers looked at records of all births in North Carolina over an eight-year period and matched 625,042 births with corresponding public school records. Researchers noted 1.3 percent of male children and 0.4 percent of female children had autism diagnoses. For both genders, the percent of diagnoses was 35 times higher among children after induced labor rather than natural labor.
The findings of this study are similar to other risk factors of autism, which include giving birth at an older age, and babies born 34 weeks of age.
A previous report by the Centers for Disease Control and Prevention stated that one in every 88 children in the United States is autistic, with the disorder being more common among boys than girls. However, USA Today published a report earlier in March suggesting this number has risen drastically since 2007. The current statistics reveal that 1 in every 50 American children is autistic.
"The scientific community has long looked for environmental contributors to the rising rates of autism in the United States," said Marie Lynn Miranda, PhD, senior author and dean of the University of Michigan School of Natural Resources and Environment. "This study provides preliminary evidence of an association between autism and labor induction/augmentation, especially among male children."
