The influence of multiple occupational exposures on absence from work in pregnancy: a prospective cohort study

Objectives Many women experience absence periods from work during pregnancy. Several single risk factors
for absence are identified, whereas the impact of multiple concurrent exposures has been sparsely studied. We
hypothesized that the presence of multiple occupational exposures would be associated with an increased risk
of absence from work during pregnancy.
Methods We included women from the Danish National Birth Cohort (1996–2002), pregnant with one child and
working ≥30 hours/week at interview (mean gestational week 17 (standard deviation 4.0); N=50 142). Information about five occupational exposures (job demands, job control, work posture, work shift, lifting) were retrieved
from the interview, each assigned values of 0/1, and summed into an index (0–5). The woman’s first absence from
work (both regular and related to pregnancy) after the interview was available from a nationwide administrative
register. We analyzed data with Cox regression using gestational age as the underlying time-variable.
Results Few women experienced none of the occupational exposures (3.6%) and most experienced two exposures (34.7%). Only 24.3% of the women were absent from work before gestational week 31. The number of
occupational exposures was associated with an increasing risk of absence. The adjusted hazard ratio for absence
increased from 1.3 [95% confidence interval [...]