Table 5

Relation between physical work load, weekly hours standing/walking and iatrogenic PTB stratified by hypertensive status in employed women only (n=4865)

NIatrogenic PTBAdjusted*
OR (95% CI)
Physical work load
Hypertension during pregnancyLow (ref)21241.01.0
NoModerate13701.92 (0.79–4.64)1.74 (0.69–4.38)
High4151.15 (0.23–5.32)1.10 (0.22–5.55)
Pre-existent hypertensionLow791.01.0
Moderate540.76 (0.28–3.17)0.75 (0.14–4.12)
High251.08 (0.20–5.77)0.94 (0.12–7.34)
Moderate2683.46 (1.05–11.36)3.25 (0.96–10.98)
High627.09 (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.