Does secondhand smoke during pregnancy raise the risk of cerebral palsy in babies? Research does not show a direct link between secondhand smoke exposure and cerebral palsy. Cerebral palsy stems mainly from brain injuries or issues with brain development before, during, or right after birth, often tied to oxygen shortages, infections, or premature delivery. While active maternal smoking harms fetal brain growth, studies focus more on that than on secondhand smoke for cerebral palsy specifically.
Secondhand smoke contains nicotine, carbon monoxide, and other toxins that reach the fetus through the mother’s bloodstream. These can limit oxygen supply and disrupt normal brain cell growth. For example, nicotine alters brainstem areas that control breathing and arousal, leading to lasting changes in how the brain handles low oxygen levels. This might raise general risks for brain-related problems, but no clear evidence points to cerebral palsy from passive exposure.
Active smoking during pregnancy does affect the fetal brain in ways that could overlap with cerebral palsy causes. Reports note altered serotonin systems in the brainstem, changed receptor expression, and weaker responses to low oxygen in newborns exposed in the womb. These kids often face respiratory troubles at birth, like smaller lung capacity and higher chances of severe infections needing ventilators. Brain scans also reveal issues with white matter, the insulation around nerve fibers, which supports smooth signal transmission. Poor white matter development can lead to cognitive delays or movement problems, though not always cerebral palsy.
Secondhand smoke likely poses similar but milder risks since exposure levels are lower than direct smoking. It still delivers nicotine and toxins that spark oxidative stress, inflammation, and glitches in cell growth for myelin, the brain’s protective coating. Animal and human studies link prenatal tobacco exposure to thinner frontal lobes, smaller cerebellums, and messed-up neurotransmitter signals, all key for coordination and movement. Yet, findings vary. Some epidemiology data ties maternal smoking to higher odds of autism, ADHD, or social issues, but cerebral palsy links remain unproven and mixed due to study differences.
Dose matters too. Even light exposure from others smoking nearby might subtly harm oxygen flow and brain wiring, especially in early pregnancy when the brain forms rapidly. Heavy direct smoking worsens outcomes, like stronger withdrawal symptoms in newborns and bigger lung structure changes. For secondhand smoke, the effects build gradually but could add stress during critical windows of myelination and neuron connection.
Researchers stress that while brain changes from tobacco exposure persist into childhood, they tie more to broad neurodevelopmental delays than cerebral palsy alone. More studies are needed on passive smoke, as most data covers active smokers. Avoiding all smoke exposure supports safer pregnancies.
Sources
https://www.droracle.ai/articles/643373/what-are-the-effects-of-maternal-smoking-on-a
https://pmc.ncbi.nlm.nih.gov/articles/PMC12737246/
https://nhsjs.com/2025/impact-of-maternal-negative-behaviors-on-fetal-neurological-development-and-elevated-autism-risk/
https://www.psypost.org/prenatal-thc-exposure-linked-to-lasting-brain-changes-and-behavioral-issues/
