Smoking, alcohol, and coffee consumption and pregnancy loss: a Mendelian randomization investigation

Abstract

To the Editor: I read, with interest, the findings presented by Yuan et al. (1) in their Mendelian randomization study. In their study, smoking, but not moderate alcohol or coffee consumption, was associated with increased odds of pregnancy loss; however, they did not explain the pathophysiology behind this association (1). In this letter, I will briefly explain some of the deleterious effects of smoking exposure during pregnancy and its link to pregnancy loss. I will also highlight some points that need further clarification in the study by Yuan et al.