According to a new study by BC Children’s Hospital investigators, epidural analgesia during labour and delivery is not associated with autism spectrum disorder (ASD) in children.
“Our population-based study initially found a small increase in the risk of ASD that met the threshold for statistical significance,” said lead author Dr. Gillian Hanley, affiliate investigator with BC Children’s Hospital and assistant professor in the department of obstetrics and gynecology at the University of British Columbia (UBC). “But when we adjusted the analysis for factors that included diabetes, pregnancy-induced hypertension and gestational age at birth, the findings did not provide strong supporting evidence for this association.”
To assess whether an association exists between maternal epidural analgesia during labour and delivery with ASD in offspring, Dr. Hanley and colleagues followed 388,254 children born via vaginal delivery in British Columbia from April 1, 2000, through Dec. 31, 2014.
By the end of the followup on Dec. 31, 2016, 1.34 per cent of the children had been diagnosed with ASD. The proportion of the children diagnosed with ASD was 1.53 per cent in the group that were exposed to epidural analgesia and 1.26 per cent in the group that were not exposed. When the analysis was adjusted for factors including smoking during pregnancy, maternal body mass index (BMI) and the child’s sex, the difference in the proportion of children diagnosed with ASD was insignificant.
"The lack of an important association between epidural use during labour and delivery and ASD is reassuring,” said senior author Dr. Tim Oberlander, BC Children’s Hospital investigator and developmental pediatrician and professor in pediatrics at UBC.
“Our study provides more evidence that a previously reported ASD risk is really a reflection of differences between the groups of women who do and do not use epidurals.”
Investigators were also able to consider mothers who delivered more than one child during the study period to examine whether a mother was more likely to have used an epidural during a labour and delivery when her child was diagnosed with ASD, compared to when her child was not diagnosed with ASD. This controlled for other important factors that are likely to remain constant within a woman over time, such as genetics and propensity to use medical care. There was no association between epidural use during labour and delivery and ASD in this analysis.
Epidural analgesia is commonly used for pain relief during labour and delivery, with rates reported to be as high as 57 per cent in Canada. Epidural analgesia has a good safety profile and appears to relieve labour pain more effectively than opioid medications, but few studies have examined long-term outcomes associated with epidural analgesia.
“Given that millions of newborns are exposed to epidural analgesia annually, determining associations between this exposure and ASD is important,” said Dr. Hanley. "We are always trying to better understand associations between fetal exposures and ASD, but it is equally important to reassure women when an association that has been previously reported does not hold up when examined using different data."
"In this case, we do not think that women need to consider an increased risk for ASD in their child when making their decision around epidural use.”
The prevalence of ASD has increased from 1 in 150 in 2000 to 1 in 54 children in 2016 in the U.S. Both genetic and environmental factors and interaction between genes and the environment appear to contribute to ASD risk.
The study from Dr. Hanley and colleagues was funded by an operating grant from the Canadian Institutes of Health Research and by BC Children’s Hospital Foundation.
Dr. Hanley’s work was funded by a new investigator award from the Canadian Institutes of Health Research and a scholar award from the Michael Smith Foundation for Health Research.