Paternal body mass index is associated with decreased blastocyst development and reduced live birth rates following assisted reproductive technology

Objective: To determine the relationship between paternal body mass index (BMI), embryo development and pregnancy, and live birth outcomes after assisted reproductive technology (ART). Design: Retrospective analysis of ART cycles. Setting: Major assisted reproduction center. Patient(s): Three hundred five couples undergoing ART in a private fertility clinic. Intervention(s): No intervention was undertaken in patients involved in this study. Main Outcome Measure(s): Live birth outcomes and clinical pregnancy rates. Result(s): No significant relationship between paternal BMI and early embryo development was found. However, increased paternal BMI was associated with decreased blastocyst development, clinical pregnancy rates and live birth outcomes. Conclusion(s): To our knowledge, this is the first report linking increased paternal BMI and clinical pregnancy and live birth rates after ART treatment. Further work to elucidate the mechanisms involved is required. (Fertil Steril (R) 2011;95:1700-4. (C)2011 by American Society for Reproductive Medicine.)