Table 4

Results of the combined exposure of weekly working hours and physical work load on iatrogenic PTB in employed women only (N=4865)

NIatrogenic PTBAdjusted*
OR (95% CI)
Crude
Physical work load
Weekly working hoursLow (ref)8241.01.0
8–31Moderate7841.27 (0.25–3.59)1.16 (0.22–4.87)
High2622.58 (0.90–7.35)2.24 (0.87–6.50)
Weekly working hoursLow17901.29 (0.46–3.60)0.97 (0.34–2.76)
≥32Moderate9192.01 (0.69–5.80)1.25 (0.42–3.72)
High2424.92 (1.55–13.96)3.42 (1.04–8.21)
  • Goodness of fit tests showed no evidence of lack of fit (p>0.40 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; PTB, preterm birth.