ReviewWorking conditions and adverse pregnancy outcome: a meta-analysis
Section snippets
Data sources
Relevant studies were identified by a computer search of English-language abstracts in the MEDLINE database for the years 1966 to August 1999. A variety of searches were conducted using combinations of the following medical subject heading terms: standing, posture, work, workload, working conditions, shift, occupational exposure, occupational diseases, lifting, pregnancy complications, pregnancy, small for gestational age (SGA), fetal growth restriction (FGR), preterm, and labor. We
Methods of study selection
We followed the systematic guidelines proposed by Thacker et al38 for meta-analysis. We extracted 58 articles using this search strategy, of which 29 met the eligibility criteria. Through personal communications with authors who provided restratified data, we were able to include six studies39, 40, 41, 42, 43, 44 that did not initially meet our eligibility criteria for some or all comparisons. Prospective cohort, cross-sectional, and case control studies examining the association between
Tabulation, integration, and results
Our outcomes of interest were preterm birth, hypertension or preeclampsia, and SGA. We constructed two-by-two tables from data provided in the original papers. Because some, but not all, original authors adjusted their odds ratios (ORs) on the basis of demographic data, we used raw data from the studies rather than ORs. The meta-analysis was conducted using the Peto-modified Mantel-Haenszel method,69 and the results confirmed using the DerSimonian and Laird random effects method.70 Ninety-five
Discussion
Our analyses suggest that working conditions may significantly influence a woman’s risk of an adverse pregnancy outcome. The significant positive associations between physically demanding work and prolonged standing with preterm birth, and between physically demanding work with SGA did not vary by meta-analytic method or by subgroup analysis. Likewise, the associations between high cumulative work fatigue score and shift work with preterm birth, and between physically demanding work and
References (78)
- et al.
The changing pattern of infant mortality in the USThe role of prenatal factors and their obstetrical implications
Int J Gynaecol Obstet
(1993) Are physical activity and employment related to preterm birth and low birthweight?
Am J Obstet Gynecol
(1993)- et al.
Work in pregnancyIts evolving relationship with perinatal outcome (a review)
Soc Sci Med
(1986) - et al.
The active-duty military pregnancyA new high-risk category
Am J Obstet Gynecol
(1977) - et al.
Pregnancy among obstetriciansA comparison of births before, during, and after residency
Am J Obstet Gynecol
(1987) - et al.
Factors associated with preterm birth in Cardiff, Wales. I. Univariable and multivariable analysis
Am J Obstet Gynecol
(1995) - et al.
Female health workersAn obstetric risk group
Int J Gynaecol Obstet
(1996) - et al.
Male and female occupation in relation to miscarriage and preterm delivery in Central North Carolina
Ann Epidemiol
(1997) - et al.
Metaanalysis for the obstetrician-gynecologist
Am J Obstet Gynecol
(1996) - et al.
Is preterm delivery still related to physical working conditions in pregnancy?
J Epidemiol Commun Health
(1991)