No hyperlink between epidurals and autism, two research affirm | Spectrum
Sharp Relief: After reviewing a variety of potentially confusing factors, two new studies show no association between autism and epidural anesthesia.
RapidEye / iStock
The epidural anesthesia commonly given to pregnant women during labor is not linked to autism in children, according to two studies published today in the Journal of the American Medical Association.
The results contradict a study published last October that apparently linked epidural anesthesia in women in California to a slightly increased risk of autism in their children. This study attracted widespread criticism and concern from researchers and medical societies for failing to consider confounding factors such as a family history of psychiatric illness. In April, a follow-up study in Manitoba, Canada that controlled a few additional factors found no such association.
“There isn’t really solid evidence in any of the studies that epidural labor analgesia causes autism,” said Cynthia Wong, professor of anesthesia at the University of Iowa in Iowa City, who commented on the new studies. “I don’t think clinicians or parents need to take that into account at this point.”
The two new studies further examine the relationship with different populations and statistical methods. In one, the researchers examined the health records of 388,254 children born between 2000 and 2014 in British Columbia, Canada. Because British Columbia has a centralized autism assessment network, the majority of children in the study went through the same screening and diagnostic process that did not apply to participants in the previous studies.
About 1.5 percent of Canadian children exposed to epidural anesthesia were diagnosed with autism compared with 1.3 percent of children not exposed, suggesting a small association.
But further analysis of the data weakened the finding. To control some factors such as maternal genetics and socioeconomic status, the researchers repeated the analysis in women with multiple births, which resulted in at least one child with and one without autism. They found that when the autistic child was born, the women were no more likely to have epidural anesthesia than the non-autistic.
Make adjustments:
In another study, the researchers analyzed data from 479,178 children born in Denmark between 2006 and 2013. In contrast to the other three studies, this analysis controlled the family history of autism and the mother’s psychiatric history, both of which are linked to an increased likelihood of autism. The researchers found no significant association between autism and epidural anesthesia.
“The assessment of this relationship is an excellent example of why confounders are almost always to be considered in an observational study,” says Anders Mikkelsen, obstetrician and doctoral student at Copenhagen University Hospital – Rigshospitalet in Denmark and lead researcher of the Danish study. “Personally, I would have no qualms about recommending labor epidural anesthesia to patients or family members seeking advice on labor pain management.”
All four studies also identified differences between parents who received and did not receive epidural anesthesia. For example, people who received epidural anesthesia tended to be younger and more likely to have preeclampsia than those who did not – both factors linked to autism. And women who received epidural anesthesia were more likely to have had psychiatric illness and their children were more likely to have one parent with autism. The differences suggest that none of the studies completely eliminated confounding factors, Wong wrote in the comment.
“This is very complicated observational research,” said Gillian Hanley, assistant professor of obstetrics and gynecology at the University of British Columbia and lead researcher on the Canadian study. “It is valuable in the long run if several people do it, and do it slightly differently, and do it in different populations and with different dates, to give us the correct answer to that question.”
Taken together, the studies are “comforting” that PDAs are not associated with autism, says Hanley. Nevertheless, the researchers should try to find out which confounding factors lead to both epidural anesthesia and an increased rate of autism diagnoses.
“We owe it to women to sort that out,” says Hanley.
