Table 2 Distribution of cases among Robson classes (A) and prevalence of CS stratified for Robson classes (B)

A)

Group 1 (2672)

Group 2 (2325)

p

 1

23.02% (615/2672)

22.54% (524/2325)

0.687

 2a

11.64% (311/2672)

12.60% (293/2325)

0.298

 2b

1.80% (48/2672)

1.51% (35/2325)

0.422

 3

27.32% (730/2672)

27.10% (630/2325)

0.859

 4a

9.47% (253/2672)

8.13% (189/2325)

0.096

 4b

0.94% (25/2672)

0.60% (14/2325)

0.181

 5a

12.39% (331/2672)

12.95% (301/2325)

0.554

 5b

1.98% (53/2672)

2.41% (56/2325)

0.305

 6

2.25% (60/2672)

2.19% (51/2325)

0.901

 7

1.01% (27/2672)

1.46% (34/2325)

0.147

 8

1.57% (42/2672)

1.46% (34/2325)

0.752

 9

0.60% (16/2672)

0.30% (7/2325)

0.121

 10

6.03% (161/2672)

6.75% (157/2325)

0.294

B)

CS in group 1

CS in group 2

Difference (%)

p

 1

26.67% (164/615)

16.22% (85/524)

−10.45

< 0.01

 2a

39.23% (122/311)

29.01% (85/293)

−9.22

< 0.01

 2b

100.00% (48/48)

100.00% (35/35)

0

1.000

 3

3.70% (27/730)

2.38% (15/630)

−1.32

0.161

 4a

12.65% (32/253)

3.70% (7/189)

−8.86

< 0.01

 4b

100.00% (25/25)

100.00% (14/14)

0

1.000

 5a

64.05% (212/331)

51.50% (155/301)

−12.55

< 0.01

 5b

100.00% (53/53)

96.43% (54/56)

−3.57

0.165

 6

98.33% (59/60)

96.08% (49/51)

−2.25

0.465

 7

96.30% (26/27)

85.29% (29/34)

−11.01

0.152

 8

71.43% (30/42)

47.06% (16/34)

−24.37

0.031

 9

100.00% (16/16)

100.00% (7/7)

0

1.000

 10

42.86% (69/161)

35.03% (55/157)

−7.83

0.153