Average time in days for ART-produced embryos to reach a given developmental stage. Embryos were cultured in CMRL/BRL (yellow triangles), KSOM-AA supplemented with 10% fetal calf serum (pink squares) or HECM-9 with albumin (blue diamonds). M, morula; B, blastocyst; XB, expanded blastocyst. The results for CMRL/BRL coculture and KSOM-AA came from Weston and Wolf  and the embryos were produced by IVF while for culture in HECM-9, the results are from Wolf and coauthors  with the embryos produced by ISCI. Estimated in vivo developmental rates (open circles) have been included for reference purposes .