Labor epidural analgesia and autism spectrum disorder in 3-year-old offspring based on data from the Japan Environment and Children's Study: a prospective cohort study.

Objective: To evaluate the association between labor epidural analgesia (LEA) and autism spectrum disorder (ASD) in 3-year-old offspring in Japan.

Methods: Prospective cohort study utilizing the Japan Environment and Children's Study, the largest nationwide birth cohort study. A total of 65,742 live singleton offspring were enrolled between January 2011 and March 2014. Offspring born via cesarean delivery or with confirmed chromosomal abnormalities were excluded. Multivariate logistic regression analyses were conducted to estimate adjusted odds ratios (aOR) and 95% confidence intervals (CI), accounting for maternal, paternal, and perinatal covariates. Subgroup analyses were performed based on the sex of the offspring. The primary outcome was the diagnosis of ASD at age 3.

Results: Among the 65,742 offspring (33,684 boys [51.2%]; mean maternal age, 31.1 [4.9] years), 1,324 (2.0%) were exposed to LEA. ASD was diagnosed in 14 (1.1%) offspring exposed to LEA and 257 (0.4%) not exposed to LEA by age 3. After adjusting for potential confounders, multivariate logistic regression revealed that LEA was associated with an increased risk of ASD (aOR: 2.23; 95% CI: 1.28-3.87). Subgroup analysis indicated that the association was significant in male offspring (aOR: 2.55; 95% CI: 1.40-4.65), but not in female offspring (aOR: 1.41; 95% CI: 0.34-5.91).

Conclusion: This study suggests a mild association between LEA and ASD in 3-year-old male offspring. However, the findings should be cautiously interpreted given the limited number of ASD cases in this study. Causal relationships cannot be established since this was an observational study.