Objective:To determine the efficacy of embryo outgrowth on fibronectin as a low cost, high throughput altative to embryo transfer to model embryo attachment and the initial stages of implantation.Methods:Following in vitro embryo culture, embryo quality was assessedviaembryo transfer or embryo outgrowth with metabolic assessment.Results:This study shows that blastocysts attach to fibronectin at the same rate that they implantin vivo, and that the carbohydrate utilisation of embryos that successfully outgrow is comparable to those that are able to develop into a fetus.Conclusions:Embryo outgrowth is a suitable altative endpoint to embryo transfer.