The effect of mTeSR1 on the morphologies (A) and outgrowth rates (B) of blastocysts. Major morphologies (flat and dome shapes) of blastocyst outgrowth at day 7 of outgrowth culture are shown. Outgrowth rates were calculated as the ratio of dome-shaped colonies to plated blastocysts. Error bars represent the standard error of the mean (± SEM).