| Singletons | Twins | |||
|---|---|---|---|---|
| OR (95% CI) | P Value | OR (95% CI) | P Value | |
| Unadjusted | 0.92 (0.71, 1.18) | 0.49 | 0.83 (0.69, 0.99) | 0.04 |
| Adjusted for hospital | 0.95 (0.74, 1.22) | 0.69 | 0.85 (0.71, 1.03) | 0.09 |
| Adjusted for year | 0.91 (0.71, 1.17) | 0.47 | 0.83 (0.69, 0.99) | 0.04 |
| Adjusted for hospital and year | 0.95 (0.74, 1.22) | 0.66 | 0.85 (0.70, 1.02) | 0.08 |
| Adjusted for gestation | 0.62 (0.45, 0.84) | 0.002 | 0.71 (0.57, 0.90) | 0.004 |
| Adjusted for hospital, gestation and year | 0.68 (0.49, 0.93) | 0.02 | 0.76 (0.60, 0.97) | 0.03 |