US Research Suggests Labour Induction Could Increase Risk of Autism

Research carried out in the United States and  published in JAMA Pediatrics suggests labour induction could increase risk of autism.

The retrospective analysis by researchers at Duke Medicine and the University of Michigan is the largest of its kind and also indicates chances are higher if the baby is male.

The findings do not prove cause and effect, but suggest the need for more research, particularly as labour induction and augmentation have been used more frequently in the US in recent years.

“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. “However, these studies produced conflicting results and consisted of a relatively small number of subjects.

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, which indicated whether children were diagnosed with autism. Approximately 1.3 per cent of male children and 0.4 per cent of female children had autism diagnoses. In both male and female children, the percentage of mothers who had induced or augmented labour was higher among children with autism compared with those who did not have autism.

Dr Gregory said the increased risk associated with induction and augmentation is similar to other known risk factors for developing autism, including a mother being older or a baby being born before 34 weeks of age. Additional analysis suggests that the absence of induction and augmentation might eliminate two in every 1,000 autism cases among male children born to induced or augmented mothers.

“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 labour induction/augmentation, especially among male children.”

At the same time, Dr Miranda cautioned that further investigation is warranted to understand these preliminary results. “Additional studies are needed to differentiate among potential explanations of the association, such as: underlying pregnancy conditions requiring the eventual need to induce/augment, the events of labour and delivery associated with induction/augmentation, and the specific treatments and dosing used to induce/augment labour (e.g., exogenous oxytocin and prostaglandins),” Miranda said.

The researchers noted that some information that could have benefitted their analyses was not available, including detailed data on the children’s autism diagnoses. No information was available on the severity of autism, nor were records available for children diagnosed with autism who did not attend a public school. The researchers also did not have access to the full maternal or child medical records, which would provide more detailed information on the pregnancy and events of labour and delivery