Specific physical activities or working conditions are suspected for increasing the risk of preterm birth (PTB). The aim of this meta-analysis is to review and summarize the pre-existing evidence on the effect of shift work or long working hours on the risk of PTB.
We conducted a systematic search in MEDLINE and EMBASE (1990–2013) for observational and intervention studies with original data. We only included articles that met our specific criteria for language, exposure, outcome, data collection and original data that were of at least of moderate quality. The data of the included studies were pooled.
Eight high-quality studies and eight moderate-quality studies were included in the meta-analysis. In these studies, no clear or statistically significant relationship between shift work and PTB was found. The summary estimate OR for performing shift work during pregnancy and the risk of PTB were 1.04 (95 % CI 0.90–1.20). For long working hours during pregnancy, the summary estimate OR was 1.25 (95 % CI 1.01–1.54), indicating a marginally statistically significant relationship but an only slightly elevated risk.
Although in many of the included studies a positive association between long working hours and PTB was seen this did reach only marginal statistical significance. In the studies included in this review, working in shifts or in night shifts during pregnancy was not significantly associated with an increased risk for PTB. For both risk factors, due to the lack of high-quality studies focusing on the risks per trimester, in particular the third trimester, a firm conclusion about an association cannot be stated.
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Bonzini M, Coggon D, Palmer KT (2007) Risk of prematurity, low birth weight and pre-eclampsia in relation to working hours and physical activities: a systematic review. Occup Environ Med 64:228–243
Bonzini M, Coggon D, Godfrey K et al (2009) Occupational physical activities, working hours and outcome of pregnancy: findings from the Southampton Women’s Survey. Occup Environ Med 66:685–690
Bonzini M, Palmer KT, David C, Michele C, Antonella C, Ferrario MM (2011) Shift work and pregnancy outcomes: a systematic review with meta-analysis of currently available epidemiologic studies. Br J Obstet Gynaecol 118(12):1429–1437
Both M, Overvest MA, Wildhagen MF, Golding J, Wildschut HIJ (2010) The association of daily physical activity and birth outcome: a population-based cohort study. Eur J Epidemiol 25:421–429
Cerón-Mireles P, Harlow SD, Sánchez-Carrillo CI (1996) The risk of prematurity and small-for-gestational-age birth in Mexico City: the effects of working conditions and antenatal leave. Am J Public Health 86(6):825–831
Croteau A, Marcoux S, Brisson C (2007) Working activity in pregnancy, preventive measures, and the risk of preterm delivery. Am J Epidemiol 166:951–965
Dutch Society for occupational Medicine (NVAB) (2007) Practice guideline pregnancy, postpartum period and work: advice and guidance by the occupational physician. http://nvab.artsennet.nl/Richtlijnen.htm
Emancipatiemonitor (2012) Central Bureau of Statistics (CBS) and The Netherlands Institute for Social Research (SCP). http://www.cbs.nl/NR/rdonlyres/F5DF2565-1721-40A4-BF16-FF7852AAC53D/0/emancipatiemonitor2012.pdf
Escribà-Agüir V, Perez-Hoyos S, Saurel-Cubizolles MJ (2001) Physical load and psychological demand at work during pregnancy and preterm birth. Int Arch Occup Environ Health 74:583–588
Higgins JPT, Green S (eds) (2011) Cochrane handbook for systematic reviews of interventions version 5.1.0 (updated March 2011). The cochrane collaboration. www.cochrane-handbook.org
Jansen PW, Tiemeier H, Verhulst FC, Burdorf A, Jaddoe VWV, Hofman A, Moll HA, Verburg BO, Steegers EAP, Mackenbach JP, Raat H (2010) Employment status and the risk of pregnancy complications: the Generation R Study. Occup Environ Med 67:387–394
Lawson CC, Whelan EA, Hibert EN, Grajewski B, Spiegelman D, Rich-Edwards JW (2009) Occupational factors and risk of preterm birth in nurses. Am J Obstet Gynecol 200:51.e1–51.e8
Liberati A, Altman DG, Tetzlaff J, Mulrow C, Gøtzsche PC, Ioannidis JPA, Clarke M, Devereaux PJ, Kleijnen J, Moher D (2009) The PRISMA-statement for reporting systematic reviews and meta-analyses of studies that evaluate health care interventions: explanation and elaboration. PloS Med 6(7):e1000100. doi:10.1371/journal.pmed.1000100
Luke B, Mamelle N, Keith L, Munoz F, Minogue J, Papiernik E, Johnson TRB (1995) The association between occupational factors and preterm birth: a United States nurses’ study. Am J Obstet Gynecol 173:849–862
Mozurkewich EL, Luke B, Avni M, Wolf FM (2000) Working conditions and adverse pregnancy outcome: a meta-analysis. Obstet Gynecol 95:623–635
NHS Plus. Royal College of Physicians (2009) Physical and shift work in pregnancy: occupational aspects of management. A national Guideline
Niedhammer I, O’Mahony D, Daly S, Morrison JJ, Kelleher CC (2009) Occupational predictors of pregnancy outcome in Irish working women in the Lifeways cohort. Br J Obstet Gyneacol 16:943–952
Nurminen T (1995) Female noise exposure, shift work, and reproduction. J Occup Environ Med 37(8):945–950
Pompeii LA, Savitz DA, Evenson KR, Rogers B, McMahon M (2005) Physical exertion at work and the risk of preterm delivery and small-for-gestational-age birth. Obstet Gynecol 106:1279–1288
Rothman KL, Greenland S (1998) Modern epidemiology, 2nd edn. Lippincott Williams and Wilkins, Philadelphia
Saurel-Cubizolles MJ, Zeitlin J, Lelong N, Papiernik E, Di Renzo GC, Bréart G (2004) Employment, working conditions, and preterm birth: results from the Europop case-control survey. J Epidemiol Commun Health 58:395–401
Scottish Intercollegiate Guidelines Network (SIGN) Methodology. http://www.sign.ac.uk/methodology/index.html
Shirangi A, Fritschi L, Holman DJ (2009) Associations of unscavenged anesthetic gases and long working hours with preterm delivery in female veterinarians. Obstet Gynecol 113:1008–1017
Snijder CA, Brand T, Jaddoe V, Hofman A, Mackenbach JP, Steegers EAP, Burdorf A (2012) Physically demanding work, fetal growth and the risk of adverse birth outcomes. The Generation R Study. Occup Environ Med 69:543–550
Stinson JC, Lee KL (2003) Premature labor and birth: influence of rank and perception of fatigue in active duty military women. Mil Med 168(5):385–389
Tuntiseranee P, Geater A, Chongsuvivatwong V (1998) The effect of heavy maternal workload on fetal growth retardation and preterm delivery: a study among Southern Thai women. J Occup Environ Med 40(11):1013–1021
Xu X, Ding M, Li B, Christiani DC (1994) Association of rotating shift work with preterm births and low birth weight among never smoking women textile workers in China. Occup Environ Med 51:470–474
Zhu JL, Hjollund NH, Olsen J (2004) Shift work, duration of pregnancy, and birth weight: the National Birth Cohort in Denmark. Am J Obstet Gynaecol 191:285–291
The authors wish to thank Dr. J.H.A.M. Verbeek (Finnish Institute of Occupational Health, Kuopio, Finland) for his help with the meta-analysis.
Conflict of interest
The authors declare that they have no conflict of interest.
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van Melick, M.J.G.J., van Beukering, M.D.M., Mol, B.W. et al. Shift work, long working hours and preterm birth: a systematic review and meta-analysis. Int Arch Occup Environ Health 87, 835–849 (2014). https://doi.org/10.1007/s00420-014-0934-9
- Preterm birth
- Shift work
- Working hours