Caffeine, alcohol, smoking, and reproductive outcomes among couples undergoing assisted reproductive technology treatments

During the past decade, as the use of assisted reproductive technologies (ART) has continued to increase worldwide, research investigating whether modifiable lifestyle factors, such as alcohol, caffeine, and smoking, may affect ART outcomes has grown. Despite the vast literature, there is still uncertainty regarding the effects of some of these exposures on ART outcomes. The objective of this review is to summarize the epidemiologic literature on intakes of caffeine and alcohol, smoking, and reproductive outcomes among women undergoing ART. Of the five epidemiologic studies on caffeine intake and ART outcomes, only one found a significant negative effect of caffeine intake on live birth following ART. There have been six epidemiologic studies exploring whether alcohol intake is associated with fertility outcomes among women undergoing ART. Three studies assessed current alcohol consumption and observed a negative effect on outcomes such as fertilization, embryo quality, and implantation. When alcohol intake in the year before treatment was assessed, no relationships were observed with clinical outcomes following ART. Finally, numerous epidemiologic studies and a handful of meta-analyses have confirmed that female current smokers have worse ART outcomes compared with nonsmokers. Although former smokers tend to have better ART outcomes than current smokers, very few individual studies have investigated the influence of smoking cessation on ART outcomes. Literature on male smoking, drinking, and caffeine habits in relation to ART outcomes is even sparser and inconsistent, making it difficult to draw strong conclusions on that topic. In summary, there is little evidence supporting a detrimental effect of moderate caffeine intake on ART outcomes. Current consumption of alcohol may have a negative effect on ART outcomes, but at present the evidence is limited. Women who currently smoke cigarettes have been consistently found to have poorer ART outcomes, including reduced live birth rates, but a quantification of the benefits of smoking cessation is lacking.