Occupational lifting during pregnancy and risk of fetal death in a large national cohort study

Scand J Work Environ Health. 2013 Jul;39(4):335-42. doi: 10.5271/sjweh.3335. Epub 2012 Dec 3.


Objective: The aim of the present study was to examine the association between occupational lifting and the risk of fetal death according to gestational age.

Methods: We used data from the Danish National Birth Cohort (1996-2002). Among 71,500 occupationally active women, 2886 experienced a fetal death. Information on lifting and relevant covariates was collected in interviews around week 16 of pregnancy. The majority of fetal losses (N=2032) happened before the scheduled interview, and exposure data were collected retrospectively from these women. We analyzed early miscarriage (≤12 weeks), late miscarriage (13-21 weeks), and stillbirth (≥22 weeks), using Cox-regression models with gestational age as the underlying time variable.

Results: The adjusted early miscarriage risk increased with frequency of daily lifts and total burden lifted per day. For example, the hazard ratio was 1.38 [95% confidence interval (95% CI) 1.10-1.74] for a total weight load per day of 101-200 kg and 2.02 (95% CI 1.23-3.33) for a daily load >1000 kg as compared to non-lifters (P for trend <0.0001). Late miscarriage was associated with total daily weight load (P for trend=0.0073) but not with number of lifts per day. There was no association between occupational lifting and stillbirth.

Conclusions: In the present study, the risk of miscarriage increased with the number of lifts and total burden lifted per day at work. There may be a case for advising pregnant women against heavy lifting in particular during early pregnancy.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Denmark
  • Female
  • Fetal Death*
  • Humans
  • Lifting*
  • Occupational Health*
  • Pregnancy
  • Proportional Hazards Models
  • Risk Factors