Over the years, we have seen a number of research studies which suggested a link between maternal smoking during pregnancy and adverse psychiatric outcomes in offspring, including increased risk for bipolar disorder, schizophrenia, and attention-deficit/hyperactivity disorder (ADHD). In a recent article published in JAMA Psychiatry, researchers reported on the results of a population-based cohort study of 1.7 million Swedish offspring in order to determine if maternal smoking during pregnancy was associated with an increased risk of severe mental illness in the offspring.
Compared with children with no exposure to smoking during pregnancy, those with higher levels of smoking exposure had an increased risk of severe mental illness (hazard ratio [HR 1.51], 95% CI 1.44-1.59).
However, when the researchers tried to control for potential genetic and familial confounding factors by looking at the risk of severe mental illness in sibling pairs, this association was diminished. In siblings where one was exposed to maternal smoking during pregnancy and the other was not, risk for severe mental illness did not differ significantly between the two (moderate smoking: HR, 1.09; 95% CI, 0.94-1.26; high smoking: HR, 1.14; 95% CI, 0.96-1.35).
While these findings may be reassuring, smoking during pregnancy was associated with other adverse outcomes, including increased risk of small-for-gestational-age infants (high smoking: OR 1.83, 95% CI 1.66-2.02) and preterm birth (high smoking: OR 1.22, 95% CI 1.13-1.32) in exposed versus unexposed siblings. In addition, we cannot exclude the possibility that smoking during pregnancy may be associated with less severe forms of mental illness, including ADHD.
The American College of Obstetricians and Gynecologists (ACOG) has issued recommendations to providers regarding efforts to support smoking cessation in pregnant and postpartum women. Despite these recommendations, it is estimated that 10% of women in the United States continue to smoke during pregnancy.
Ruta Nonacs, MD PhD
Quinn PD, Rickert ME, Weibull CE, Johansson ALV, Lichtenstein P, Almqvist C, Larsson H, Iliadou AN, D’Onofrio BM. Association Between Maternal Smoking During Pregnancy and Severe Mental Illness in Offspring. JAMA Psychiatry. 2017 May 3.
No Link Between Mom’s Smoking, Mental Illness in Kids (Medpage Today)
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