| Risk factors | a OR-95% CI* | a P** |
| Age | 1.9 [1 - 3] | 0.05 |
| Passive smoking | 1.770 [1.222 - 2.256] | 0.03 |
| History of LBW*** | 2.225 [1.454 -3.403] | 0.00 |
| History of still birth | 2.230 [0.792 - 2.387] | O.2 (NS) |
| History of hypertension | 3.01 [1.93 - 3.02] | 0.01 |
| Primiparity | 2.23 [1.37 - 3.63] | 0.01 |
| Gestational hypertension | 3.458 [2.118 - 5.646] | 0.00 |
| Infection | 3.480 [1.621 - 7.473] | 0.001 |
| Premature membrane rupture | 3.113 [2.001 - 4.844] | 0.00 |
| Twin pregnancy | 1.3 [0.93 - 5.9] | 0.056 |
| Anemia | 2.627 [1.680 - 4.106] | 0.00 |