Table 2 Comparison of embryonic developmental outcomes and abnormal cleavage patterns among the four groups.

From: Delayed second polar body extrusion increases abnormal cleavage risk and impairs embryonic developmental potential: a retrospective time-lapse study

Group

Pb2 extrusion time

0–3 h

> 3–4 h

> 4–5 h

> 5 h

Fertilization rate (%)

99.07 (1697/1713)

99.24 (910/917)

98.00 (294/300)

98.40 (185/188)

2PN fertilization rate (%)

94.86 (1625/1713)c

96.29 (883/917)e

95.00 (285/300)f

85.11 (160/188)

2PN cleavage rate (%)

99.75 (1621/1625)c

99.43 (878/883)

99.65 (284/285)

98.13 (157/160)

Day3 high-quality embryo rate (%)

58.36 (946/1621)ac

51.94 (456/878)e

52.82 (150/284)f

40.76 (64/157)

Blastocyst formation rate (%)

65.86 (739/1122)abc

57.95 (357/616)e

52.36 (100/191)f

39.34 (48/122)

High-quality blastocyst formation rate (%)

19.25 (216/1122)abc

12.01 (74/616)e

10.99 (21/191)f

4.10 (5/122)

Available blastocyst formation rate (%)

43.23 (485/1122)abc

33.60 (207/616)e

30.89 (59/191)

21.31 (26/122)

Abnormal cleavage patterns

 Abnormal cleavage rate (%)

34.79 (564/1621)ac

39.98 (351/878)

39.08 (111/284)

43.95 (69/157)

 DC (%)

12.46 (202/1621)c

12.87 (113/878)e

16.55 (47/284)

21.66 (34/157)

 RC (%)

4.19 (68/1621)

4.78 (42/878)

4.93 (14/284)

3.82 (6/157)

 CC (%)

3.82 (62/1621)ac

5.81 (51/878)

4.58 (13/284)

8.92 (14/157)

 MN (%)

8.64 (140/1621)c

9.57 (84/878)e

6.69 (19/284)

3.82 (6/157)

 Mix (%)

5.66 (92/1621)

6.95 (61/878)

6.34 (18/284)

5.73 (9/157)

  1. DC direct cleavage, RC reverse cleavage, CC chaotic cleavage, MN Multinucleation, Mix mixed abnormal cleavage.
  2. aRepresents P < 0.05, compared with the > 3–4 h group.
  3. bRepresents P < 0.05, compared with the > 4–5 h group.
  4. cRepresents P < 0.05, compared with the > 5 h group.
  5. dRepresents P < 0.05, compared with the > 4–5 h group.
  6. e, fRepresents P < 0.05, compared with the > 5 h group.
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