Table 2.
Embryo parameters among the different groups
| Characteristics | < 7-cell | 7–9-cell | 10–13-cell | > 13-cell | P-value |
|---|---|---|---|---|---|
| Number of cycles | 110 | 743 | 282 | 84 | |
| Evenness of day 3 embryo (%) | < 0.001 | ||||
| 0 | 6.36 (7/110) | 22.75 (169/743)a | 12.41 (35/282)b | 21.43 (18/84)a | |
| 1 | 85.45 (94/110) | 73.76 (548/743)a | 86.17 (243/282)b | 78.57 (66/84) | |
| 2 | 8.18 (9/110) | 3.50 (26/743) | 1.42 (4/282)a | 0.00 (0/84)a | |
| Fragmentation of day 3 embryo (%) | < 0.001 | ||||
| < 10% | 23.64 (26/110) | 40.51 (301/743)a | 52.13 (147/282)a | 50.00 (42/84)a | |
| 10–25% | 43.64 (48/110) | 53.57 (398/743) | 44.33 (125/282) | 47.62 (40/84) | |
| > 25% | 32.73 (36/110) | 5.92 (44/743)a | 3.55 (10/282)a | 2.38 (2/84)a | |
| Expansion grade (%) | 0.325 | ||||
| IV | 45.45 (50/110) | 46.57 (346/743) | 38.65 (109/282) | 39.29 (33/84) | |
| V | 50.00 (55/110) | 48.59 (361/743) | 55.32 (156/282) | 57.14 (48/84) | |
| VI | 4.55 (5/110) | 4.85 (36/743) | 6.03 (17/282) | 3.57 (3/84) | |
| Grade of transferred blastocysts (%) | < 0.001 | ||||
| High-quality | 66.36 (73/110) | 86.27 (641/743)a | 93.97 (265/282)ab | 97.62 (82/84)ab | |
| Low-quality | 33.64 (37/110) | 13.73 (102/743) | 6.03 (17/282) | 2.38 (2/84) | |
| embryonic development days (%) | < 0.001 | ||||
| Day 5 | 42.73 (47/110) | 78.33 (582/743)a | 91.49 (258/282)ab | 98.81 (83/84)ab | |
| Day 6 | 57.27 (63/110) | 21.67 (161/743) | 8.51 (24/282) | 1.19 (1/84) | |
1. P value indicates differences among the four groups. P < 0.05 indicates statistically significant difference in results
2. a indicates a significant difference compared to < 7-cell group; b indicates a significant difference compared to 7–9-cell group. According to Bonferroni correction for multiple comparisons, the difference was statistically significant at P < 0.008 (0.05/6)