Blastocyst culture and transfer increases the efficiency of oocyte donation William B Schoolcraft, M.D., David K Gardner Fertility and Sterility Volume 74, Issue 3, Pages 482-486 (September 2000) DOI: 10.1016/S0015-0282(00)00685-3
Figure 1 Photomicrograph of human blastocysts developed from donated oocytes on the morning of day 5. Four blastocysts can be seen to be hatching from the zona pellucida. Schoolcraft. Blastocyst culture and transfer. Fertil Steril 2000. Fertility and Sterility 2000 74, 482-486DOI: (10.1016/S0015-0282(00)00685-3)