Table 2 Grade of transferred blastocysts among the different groups

Total transferred blastocysts

939

1224

1598

—

Expansion grade

 III

90(9.6)^a,b

81(6.6)^c

48(3.0)^d

<0.001

 IV

728(77.5)^b,c

978(79.9)^b

1216(76.1)^c

0.054

 V

101(10.8)^b

135(11.0)^b

226(14.1)^c

0.012

 VI

20(2.1)^b

30(2.5)^b

108(6.8)^c

<0.001

Good quality

 IIIAA/IIIAB/IIIBA

2(0.2)

5(0.4)

3(0.2)

0.567

 IVAA/IVAB/IVBA

120(12.8)^b

309(25.2)^c

427(26.7)^c

<0.001

 VAA/VAB/VBA

18(1.9)^b

47(3.8)^c

109(6.8)^d

<0.001

 VIAA/VIAB/VIBA

3(0.3)^b

18(1.5)^c

59(3.7)^d

<0.001

Fair quality

 IIIBB

36(3.8)^b

33(2.7)^b

14(0.9)^c

<0.001

 IVBB

383(40.8)

511(41.7)

599(37.5)

0.052

 VBB

57(6.1)

75(6.1)

95(5.9)

0.980

 VIBB

11(1.2)^b,c

10(0.8)^b

38(2.4)^c

0.002

Poor quality

 IIIAC/IIIBC/IIICA/IIICB

52(5.5)^b

43(3.5)^b

31(1.9)^c

<0.001

 IVAC/IVBC/IVCA/IVCB

225(24.0)^b

158(12.9)^c

190(11.9)^c

<0.001

 VAC/VBC/VCA/VCB

26(2.8)^b

13(1.1)^c

22(1.4)^c

0.007

 VIAC/VIBC/VICA/VICB

6(0.6)

2(0.2)

11(0.7)

0.097