Fig. 1. Time line for optimal in vitro development of stage 2 (morula) and stage 3 (blastocyst) embryos. A two-cell stage 2 embryo forms between 24 and 26 hours. A hatched stage 3 embryo forms at 144 hours. D, days; h, hours.

(From: Veeck and Zaninovic´, 2003. Reproduced with permission of the publisher, Francis and Taylor Group.)

Next