Table 2. Effect of criteria for embryo selection on subsequent pregnancy rate at day 30 and 60 post-transfer.

Criteria for embryo selection	No. of transferred blastocysts	No. (%) of pregnancies c
		Day 30	Day 60
Conventional a	22	7 (31.8)	7 (31.8)
Identified b	27	16 (59.3)	15 (55.5)

^a Transferred code 1 expanded blastocyst. ^b Transferred blastocyst identified by short duration and 2 blastomeres at first cleavage, and ≥ 6 blastomeres at onset of lag-phase. ^c Data were analyzed by the Fisher’s exact test (P = 0.08).