Relation between physical work load, weekly hours standing/walking and iatrogenic PTB stratified by hypertensive status in employed women only (n=4865)
| N | Iatrogenic PTB | Adjusted* | ||
| OR (95% CI) | ||||
| Crude | ||||
| Physical work load | ||||
| Hypertension during pregnancy | Low (ref) | 2124 | 1.0 | 1.0 |
| No | Moderate | 1370 | 1.92 (0.79–4.64) | 1.74 (0.69–4.38) |
| High | 415 | 1.15 (0.23–5.32) | 1.10 (0.22–5.55) | |
| Pre-existent hypertension | Low | 79 | 1.0 | 1.0 |
| Moderate | 54 | 0.76 (0.28–3.17) | 0.75 (0.14–4.12) | |
| High | 25 | 1.08 (0.20–5.77) | 0.94 (0.12–7.34) | |
| PIH | Low | 403 | 1.0 | 1.0 |
| Moderate | 268 | 3.46 (1.05–11.36) | 3.25 (0.96–10.98) | |
| High | 62 | 7.09 (1.72–29.19) | 6.44 (1.21–29.76) | |
Goodness of fit tests showed no evidence of lack of fit (p>0.51 for the adjusted logistic model).
Bold values indicate statistically significance at the level of p<0.05.
*Model adjusted for: parity, smoking, previous PTB, ethnicity, maternal educational level, maternal age and maternal pre-pregnancy BMI.
BMI, body mass index; PIH, pregnancy-induced hypertension; PTB, preterm birth.