Epidural Analgesia and Autism Spectrum Disorder Risk-The Challenges Inherent in Complex Observational Research

Examining the relationship between autism spectrum disorder in children whose mother had labour epidural analgesia for their birth: A retrospective cohort study

BACKGROUND

Controversy exists regarding the association between autism spectrum disorder (ASD) in children whose mother had labour epidural analgesia for their birth, as the few existing investigations have reported mixed findings.

OBJECTIVE

This study aims to evaluate the possibility of an association in our heterogeneous population.

DESIGN

A retrospective population-based cohort study.

SETTING

Vaginal deliveries that took place between the years 2005 and 2017 at Soroka University Medical Center, a tertiary referral hospital in Israel, and a follow-up on the incidence of ASD in the children.

PATIENTS

A hundred and thirty-nine thousand, nine hundred and eighty-one labouring patients and their offspring.

MAIN OUTCOME MEASURES

The incidence of children diagnosed with ASD (both hospital and community-based diagnoses) was compared based on whether their mothers had received labour epidural analgesia during their labour. A Kaplan-Meier survival curve compared cumulative incidence of ASD. A Cox proportional hazards model was used to control for relevant confounders.

RESULTS

Labour epidural analgesia was administered to 33 315 women. Epidural analgesia was more common among high-risk pregnancy groups (including pregnancies complicated with diabetes mellitus, hypertensive disorders, intrauterine growth restriction, and oligohydramnios; P  < 0.001). In a Cox proportional hazards model, the association between epidural analgesia during labour and ASD in the children lost statistical significance following adjustment for confounders such as maternal age, gestational age, hypertensive disorders, diabetes mellitus, and ethnicity [adjusted hazard ratio = 1.13, 95% confidence interval (CI), 0.96 to 1.34, P  = 0.152].

CONCLUSION

In our population, after adjusting for confounders, epidural analgesia is not independently associated with autism spectrum disorder in the children. These findings enhance our knowledge regarding the safety of epidural analgesia and enable patients to make informed decisions about their pain relief techniques during labour.

Association Between Epidural Labor Analgesia and Autism Spectrum Disorder in Offspring: A Systematic Review and Meta-Analysis

Purpose

Many studies have focused on the association between Autism spectrum disorder (ASD) and epidural labor analgesia (ELA), which is the most effective way to manage labor pain. The purpose of this meta-analysis was to summarize the current state of the association between ELA and ASD.

Methods

A search of the literature yielded 201 relevant studies, of which 7 cohort studies met our inclusion criteria. Two independent reviewers screened the inclusion results, extracted data, and assessed the risk of bias and quality of evidence.

Results

Compared to parturient who did not receive ELA, parturient who received ELA had a slightly increased risk of ASD (adjusted hazard ratio [aHR], 1.12; 95% confidence interval [CI], 1.06-1.17; I2, 69%; P < 0.001; seven studies). After excluding one literature (aHR, 1.09; 95% CI, 1.06-1.12; I2, 4%; P < 0.001; six studies). The sensitivity analyses had consistent outcomes with the main analyses involving siblings (aHR 1.11; 95% CI 1.03-1.19), cesarean section and instrumental deliveries (aHR 1.07; 95% CI 1.03-1.10), non-overlapping populations (aHR 1.09; 95% CI 1.05-1.12), full-term birth populations (aHR 1.10; 95% CI 1.06-1.14), and studies assessed to have moderate risk of bias (aHR 1.09; 95% CI 1.02-1.16).

Conclusion

This meta-analysis revealed a modest positive association between ELA and ASD, acknowledging a slight potential risk. However, it is important to note that this risk cannot be completely dismissed due to the possibility of bias and this association is based on low-quality evidence. Future studies are required to assess and mitigate different confounding biases and investigate the time-dose-response relationship.

Is There an Association between the Use of Epidural Analgesia during Labor and the Development of Autism Spectrum Disorder in the Offspring?-A Review of the Literature

Autism spectrum disorders (ASDs) are multifactorial and complex neurodevelopmental conditions usually diagnosed in the early childhood. The etiology of ASDs is commonly described as a genetic predisposition combined with an environmental impact. As a result of broadening of the diagnostic criteria the prevalence of ASDs has been increasing worldwide and the search for the modifiable factors is still on-going. Epidural analgesia (ELA) provides effective pain relief during labor and is currently the most preferred method of anesthesia during the delivery. The safety of the procedure is well-discussed and documented; nonetheless, in 2020 a single population-based study indicated an association between the use of ELA during labor and newborn risk of ASD development, which led to widespread concern. To explore the possible association between the ELA and ASD occurrence in the offspring several studies in different countries have been conducted to date. In this review we aimed to summarize the current state of knowledge concerning the association between the use of epidural analgesia during labor and risk of ASD. In conclusion, the literature review indicates that there is no significant association.

Exposure to Intrapartum Epidural Analgesia and Risk of Autism Spectrum Disorder in Offspring

IMPORTANCE

There is conflicting evidence on the association between intrapartum epidural analgesia and risk of autism spectrum disorder (ASD) in offspring.

OBJECTIVE

To evaluate the association between intrapartum epidural analgesia and the risk of ASD in offspring.

DESIGN, SETTING, AND PARTICIPANTS

This population-based cohort study was conducted in Ontario, Canada, using the health and administrative records of singleton live births by vaginal delivery between April 1, 2006, and March 31, 2014. Neonates with less than 24 weeks' gestation or weighing less than 500 g were excluded. Offspring were followed up from 18 months of age until ASD diagnosis, loss to follow-up, or the end of the study (December 31, 2020), whichever occurred first. Exposure, covariate, and outcome data were obtained using provincial health administrative databases.

EXPOSURES

Any intrapartum exposure to epidural or combined spinal-epidural analgesia.

MAIN OUTCOMES AND MEASURES

The primary outcome was ASD diagnosis after 18 months of age. Inverse probability of treatment weighting (IPTW) of Cox proportional hazards regression models was used to estimate the hazard ratio (HR) of intrapartum epidural analgesia and ASD in offspring. Offspring head injury was used as a control outcome. Models were adjusted for maternal sociodemographic factors, health behaviors, and medical and obstetrical history as well as labor, delivery, and offspring characteristics. Post hoc analyses included restriction to term neonates, a conditional within-mother analysis, exclusion of records with concomitant intrapartum pain management exposures, a complete case analysis, use of an alternative ASD definition, and estimation of the average treatment effect in the treated group.

RESULTS

Among the 650 373 mother-offspring pairs included in the study, 418 761 (64.4%) were exposed to intrapartum epidural analgesia. The mean (SD) maternal age at delivery was 29.7 (5.5) years; the offspring had a mean (SD) gestational age at delivery of 39.1 (1.6) weeks and included 329 808 male newborns (50.7%). The exposed and unexposed groups were similar in all maternal and newborn characteristics after IPTW (standardized difference <0.10). Autism spectrum disorder was diagnosed in 7546 offspring (1.8%) of mothers who received intrapartum epidural analgesia (incidence rate, 18.8 [95% CI, 18.4-19.3] per 10 000 person-years) compared with 3234 offspring (1.4%) who were unexposed (incidence rate, 14.4 [95% CI, 13.9-14.9] per 10 000 person-years). The crude HR for ASD associated with intrapartum epidural analgesia was 1.30 (95% CI, 1.25-1.36), and the IPTW-adjusted HR was 1.14 (95% CI, 1.08-1.21). Results did not qualitatively differ in post hoc analyses.

CONCLUSIONS AND RELEVANCE

Results of this study showed that intrapartum epidural analgesia was associated with a small increase in risk for ASD in offspring. The biological plausibility of this association, however, remains unclear, and the finding must be interpreted with caution.