Maternal Smoking and Autism Spectrum Disorder: A Meta-analysis.

The team pooled 15 earlier studies that asked the same question: does smoking while pregnant raise autism odds?

They ran a meta-analysis, a math tool that blends all results into one big picture.

The combined odds ratio landed at 1.02, basically no link at all.

In plain words, kids of moms who smoked during pregnancy were no more likely to have autism.

Syriopoulou-Delli et al. (2012) saw the same null result three years earlier, so the new paper backs them up.

Sung et al. (2026) later looked at 72 cohorts and found a tiny bump in autism traits. The numbers look opposite, but the bump is so small it could be noise; both groups still call the effect weak.

Tioleco et al. (2021) and Pitchford et al. (2019) show that infections with fever do raise odds, while smoking does not. This helps you triage which prenatal stories to chase.

You can stop asking new clients about mom’s smoking history as an autism risk factor. Focus staff training and parent worry on proven risks like mid-pregnancy fever or diabetes instead.

Researchers pooled 15 studies of maternal prenatal smoking and autism risk in offspring using a random-effects model. The summary odds ratio was 1.02 with a 95 percent confidence interval of 0.93 to 1.12, showing no association.

Stratifying by study design, birth year, healthcare system, and adjustment for socioeconomic status or psychiatric history did not change the result. There was no evidence of publication bias.

Non-differential misclassification of exposure was judged unlikely to have meaningfully distorted the findings.

Smoking during pregnancy carries well-documented harms, but this body of evidence does not support it as a cause of autism.

When families ask about prenatal risk factors, this null finding lets clinicians set maternal smoking aside and focus etiology discussions on better-supported variables.