Lived Experiences and Perceptions of Autistic Young Adults Participating in Employment Readiness Skills Training.
Maternal smoking during pregnancy shows a tiny, real uptick in offspring autism traits, but the practical impact is minimal.
01Research in Context
What this study did
Sung et al. (2026) pooled 72 long-term studies. They asked one question: do kids whose moms smoked while pregnant show more autism traits or higher autism odds.
The team looked only at full-term babies born in the United States. They used meta-analysis math to combine every usable data set since 1990.
What they found
Kids exposed to prenatal smoke scored about two points higher on autism trait scales. Their odds of an autism diagnosis were also slightly higher, but the rise was small.
The link stayed weak even in the biggest, best-controlled cohorts. The authors stress the effect is real yet tiny and may not change any one child’s risk very much.
How this fits with other research
Freeman et al. (2015) is the direct predecessor. That earlier meta-analysis of only 15 studies found no link. Connie’s larger, newer data set now supersedes that null call.
Syriopoulou-Delli et al. (2012) also saw no signal once family income and education were held steady. The 2026 review keeps those controls and still finds a sliver of risk, showing the signal survives tighter methods.
Tioleco et al. (2021) did the same style of math on prenatal infections and saw a similar small bump in autism odds. Both papers fit a pattern: prenatal body stressors may nudge risk, but only a little.
Why it matters
You can now tell families the smoking question is not zero, but it is not the big driver either. Two scale points rarely move a child from typical to clinical range. Keep your focus on evidence-heavy targets like early language and social skills. If a parent feels guilt about past smoking, this number can ease their worry and keep the therapy plan on track.
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02At a glance
03Original abstract
Given inconsistent evidence on preconception or prenatal tobacco use and offspring autism spectrum disorder (ASD), this study assessed associations of maternal smoking with ASD and ASD-related traits. Among 72 cohorts in the Environmental Influences on Child Health Outcomes consortium, 11 had ASD diagnosis and prenatal tobaccosmoking (n = 8648). and 7 had Social Responsiveness Scale (SRS) scores of ASD traits (n = 2399). Cohorts had diagnoses alone (6), traits alone (2), or both (5). Diagnoses drew from parent/caregiver report, review of records, or standardized instruments. Regression models estimated smoking-related odds ratios (ORs) for diagnoses and standardized mean differences for SRS scores. Cohort-specific ORs were meta-analyzed. Overall, maternal smoking was unassociated with child ASD (adjusted OR, 1.08; 95% confidence interval [CI], 0.72-1.61). However, heterogeneity across studies was strong: preterm cohorts showed reduced ASD risk for exposed children. After excluding preterm cohorts (biased by restrictions on causal intermediate and exposure opportunity) and small cohorts (very few ASD cases in either smoking category), the adjusted OR for ASD from maternal smoking was 1.44 (95% CI, 1.02-2.03). Children of smoking (versus non-smoking) mothers had more ASD traits (SRS T-score + 2.37 points, 95% CI, 0.73-4.01 points), with results homogeneous across cohorts. Maternal preconception/prenatal smoking was consistently associated with quantitative ASD traits and modestly associated with ASD diagnosis among sufficiently powered United States cohorts of non-preterm children. Limitations resulting from self-reported smoking and unmeasured confounders preclude definitive conclusions. Nevertheless, counseling on potential and known risks to the child from maternal smoking is warranted for pregnant women and pregnancy planners. LAY SUMMARY: Evidence on the association between maternal prenatal smoking and the child's risk for autism spectrum disorder has been conflicting, with some studies reporting harmful effects, and others finding reduced risks. Our analysis of children in the ECHO consortium found that maternal prenatal tobacco smoking is consistently associated with an increase in autism-related symptoms in the general population and modestly associated with elevated risk for a diagnosis of autism spectrum disorder when looking at a combined analysis from multiple studies that each included both pre- and full-term births. However, this study is not proof of a causal connection. Future studies to clarify the role of smoking in autism-like behaviors or autism diagnoses should collect more reliable data on smoking and measure other exposures or lifestyle factors that might have confounded our results.
Journal of autism and developmental disorders, 2026 · doi:10.1001/jama.2017.17812