The Interplay between Maternal Smoking and Genes in Offspring Birth Weight

It is well-established that birth weight is affected by the child’s genetic endowments and maternal smoking during pregnancy. Here, we investigate whether an interaction between genetic endowments and maternal smoking on birth weight exists. We instrument the maternal smoking decision with a genetic variant (rs1051730) located in the nicotine receptor gene CHRNA3 and deal with the underreporting of maternal smoking by using a biomarker of nicotine collected during pregnancy. We confirm that genetic endowments and maternal smoking negatively affect the child’s birth weight. However, we do not find evidence of meaningful interactions between genetic endowments and maternal smoking.