Table 4 Effects of sperm concentration in ICSI

Mean maternal age (years ± SD)

32.97 ± 5.05

31.98 ± 5.11

32.81 ± 5.05

33.94 ± 4.83

0.6257

Number of ICSI

282

373

326

651

Mean number of injected oocytes ± SD

8.04 ± 4.52

8.50 ± 4.80

7.81 ± 4.29

7.28 ± 4.24

0.0007

Fertilization rate (%)

58.29

61.87

65.30

68.95

<0.0001

Mean number of embryos at day 2 ± SD

4.40 ± 3.30

5.04 ± 3.70

4.97 ± 3.56

4.81 ± 3.55

0.1515

Mean number of embryos at day 3 ± SD

4.03 ± 3.39

4.21 ± 3.51

4.25 ± 3.30

4.17 ± 3.33

0.7636

Mean number of embryos in prolonged culture ± SD

2.15 ± 2.93

2.78 ± 3.50

2.77 ± 3.43

2.73 ± 3.23

0.0562

Mean number of obtained blastocysts ± SD

0.84 ± 1.63

1.32 ± 2.15

1.44 ± 2.10

1.36 ± 2.07

0.0014

Rate of blastocyst formation (%)

39.17

47.49

51.88

49.69

<0.0001

Mean number of transferred blastocysts ± SD

0.035 ± 0.185

0.042 ± 0.228

0.092 ± 0.300

0.093 ± 0.307

0.3593

Mean number of frozen blastocysts ± SD

0.344 ± 0.980

0.592 ± 1.230

0.610 ± 1.400

0.516 ± 1.210

0.1113

Rate of useful blastocysts (%)

45.155

48.07

48.93

44.96

0.4562

Rate of clinical pregnancies (%)

35.30

41.30

39.60

37.60

0.4980

Rate of miscarriages (%)

22.70

9.60

14.90

21.00

0.1572