Table 3.
Contribution of Robson ten obstetric groups to the overall caesarean section rate
| Robson Group | Number of women (n1) |
Relative size of Robson group (%) n1/N1 | Number of CS (n2) |
Group specific CS (%) n2/n1 |
Group input to total CS (%) n2/N2 |
Group input to overall CS rate (%) n2/N1 |
|---|---|---|---|---|---|---|
| 1 | 86 | 19.2 | 21 | 24.4 | 9.2 | 4.7 |
|
2 2a 2b |
38 19 19 |
8.5 4.3 4.3 |
32 13 19 |
84.2 68.4 100.0 |
14.0 5.7 8.3 |
7.2 2.9 4.3 |
| 3 | 136 | 30.4 | 23 | 16.9 | 10.0 | 5.1 |
|
4 4a 4b |
18 7 11 |
4.0 1.6 2.5 |
15 4 11 |
83.3 57.1 100.0 |
6.6 1.8 4.8 |
3.3 0.9 2.4 |
|
5 5.1 5.2 |
81 66 15 |
18.1 14.8 3.4 |
79 64 15 |
97.5 97.0 100.0 |
34.5 27.9 6.6 |
17.7 14.3 3.3 |
| 6 | 5 | 1.1 | 5 | 100.0 | 2.2 | 1.1 |
| 7 | 9 | 2.0 | 8 | 88.9 | 3.5 | 1.8 |
| 8 | 20 | 4.5 | 11 | 55.0 | 4.8 | 2.5 |
| 9 | 6 | 1.3 | 6 | 100.0 | 2.6 | 1.3 |
| 10 | 49 | 11.0 | 29 | 59.2 | 12.6 | 6.5 |
| Total | 447 | 100.0 | 229 | NA | 100.0 | 51.2 |
CS = Caesarean Section; N1 = Total births (447); N2 = Total CS births (229); n1 = number of women in each Robson group; n2 = number of CS births in each Robson group; NA = not applicable