Table 2 Baseline characteristic of patients in the rescue and conventional ICSI groups

Patients

124

375

91

284

Maternal age (years)

31.02 ± 3.50^ab

30.63 ± 3.85

31.32 ± 3.98^a

30.42 ± 3.79^b

Paternal age (years)

34.12 ± 5.86

33.65 ± 5.43

33.05 ± 4.68

33.85 ± 5.65

BMI (kg/m²)

21.77 ± 3.00^a

21.08 ± 2.93^*

21.07 ± 3.48^ab

21.08 ± 2.75^b

Infertility duration (years)

4.42 ± 3.03

3.93 ± 2.72

3.86 ± 2.71

3.95 ± 2.73

Maternal infertility diagnosis, n (%)

 Tubal factor

35 (28.23)

106 (28.27)

28 (30.77)

78 (27.46)

 Ovulation dysfunction

7 (5.65)

25 (6.67)

8 (8.79)

17 (5.99)

 Endometriosis

19 (15.32) ^a

19 (5.07)^*

9 (9.89) ^a

10 (3.52) ^b

 Unexplained infertility

63 (50.81)

225 (60.00)

46 (50.55)

179 (63.03)

 Follicle counts on HCG day

9.90 ± 3.22

9.74 ± 3.15

9.45 ± 3.05

9.84 ± 3.18

 No. of oocytes retrieved

12.82 ± 5.21

12.63 ± 5.59

12.47 ± 5.76

12.69 ± 5.55

 No. of oocytes injected

8.92 ± 4.54^b

10.63 ± 5.04^*

10.12 ± 4.87^ab

10.80 ± 5.09^a

Embryo outcomes per injected oocyte, n (%)

 Normal fertilization rate

859/1106 (77.67)

3125/3987 (78.38)

733/921 (79.59)

2392/3066 (78.02)

 Polyspermy rate

27/1106 (2.44)

56/3987 (1.40)^*

13/921 (1.41)

43/3066 (1.40)

 TQE rate

473/1106 (42.77)^c

1933/3987 (48.48)^*

479/921 (52.01)^a

1454/3066 (47.42)^b

 Damage oocyte rate

60/1106 (5.42)

173/3987 (4.34)

50/921 (5.43)

123/3066 (4.01)

 Total no. of TQE

4.02 ± 3.42^b

5.15 ± 3.62^*

5.26 ± 3.74^a

5.12 ± 3.60^a

 No. of embryo transferred

2.09 ± 0.38

2.14 ± 0.37

2.15 ± 0.39

2.13 ± 0.37

 No. of TQE transferred

1.75 ± 0.73^b

1.96 ± 0.63^*

1.97 ± 0.66^a

1.95 ± 0.63^a

 Endometrial thickness (mm)

11.67 ± 2.16

11.87 ± 2.56

11.62 ± 2.52

11.95 ± 2.57