Genetic and epigenetic influences associated with intrauterine growth restriction due to in utero tobacco exposure.

While many fetuses are exposed to tobacco in utero, not all experience adverse outcomes as a result of this exposure. Mechanisms leading to the attenuation of fetal birth weight and adverse pregnancy outcomes are complex. Therefore many studies have begun to focus, not only on the contribution of maternal and fetal genes to phenotypic outcome, but also on epigenetic changes associated with exposure to maternal tobacco smoke. In this review, we detail the epidemiologic evidence associating an adverse pregnancy outcome to maternal tobacco use. We provide a brief summary of studies demonstrating an association between maternal and fetal gene polymorphisms with low birth weight in response to maternal tobacco exposure. We also review the literature showing epigenetic changes in the offspring associated with in utero tobacco exposure. The complex interplay of genomic and epigenomic factors may contribute to specific phenotypic outcomes and can help begin to elucidate the differential susceptibilities to tobacco smoke in utero.