Having an epidural during childbirth was not associated with a greater risk of autism in the child, according to a study published in JAMA Pediatrics.
“We did not find evidence for any genuine link between having an epidural and putting your baby at increased risk of autism spectrum disorder,” said senior author Alexander Butwick, MD, Stanford University School of Medicine, Stanford, California.
In October 2020, a study of California births said epidural use was associated with a 37% greater risk of later autism diagnosis for children. However, the study was widely criticised for failing to account for many socioeconomic, genetic, and medical risk factors for autism — separate from the epidural — that could be more common among women who choose epidurals. Experts also noted that it was biologically implausible for epidurals to increase autism risk. Shortly after, several professional societies issued a statement saying that the study did not provide credible scientific evidence that epidurals cause autism.
The new research examined epidural use during childbirth and later diagnoses of autism in Manitoba. It included 123,175 children who were born between 2005 and 2016 and were followed until 2019.
“Manitoba has these wonderful, linked data sets that are population-wide,” said Dr. Butwick, noting that the research team was able to access information that linked together individuals’ medical records, prescriptions, other health-related data, socioeconomic information, and information about children’s academic achievements.
All of the children in the study were born via vaginal delivery and were single births. Of those studied, 38.2% of the children were exposed to epidural anaesthesia during labour. Of children exposed to epidurals during labour, 2.1% were later diagnosed with autism spectrum disorder, compared with 1.7% of children not exposed to epidurals.
The researchers then did an analysis to control for factors thought to potentially influence autism risk, including socioeconomic factors; mothers’ pre-pregnancy medical history; medical conditions during pregnancy; mothers’ smoking, alcohol and recreational drug use; mothers’ hospitalization for mental illness during pregnancy; mothers’ use of several types of prescription medications; medical complications of delivery; and factors related to the mothers’ pregnancy and labour, including the length of the pregnancy, whether labour was induced or augmented and whether the fetus was large or in distress during labour.
The researchers also analysed pairs of siblings in which the mother received an epidural during one child’s birth but not the other. This comparison gave a way to account for genetic and familial factors, which influence autism risk.
Once the researchers had adjusted for all the confounding factors, there was no statistically significant difference in autism risk between children whose mothers received epidurals during their birth and those who did not. Accounting for genetic and family-related factors reduced the difference between the groups even more.
“Our study has a stronger finding because we accounted for limitations the first study had,” said Dr. Butwick. “An epidural remains a well-established and effective means of providing pain relief during labour, with several benefits associated with it.”