Occupational factors and risk of preterm birth in nurses

Published:November 03, 2008DOI:


      We evaluated first-trimester exposures and the risk of preterm birth in the most recent pregnancy of participants of the Nurses' Health Study II.

      Study Design

      Log binomial regression was used to estimate the relative risk (RR) for preterm birth in relation to occupational risk factors, such as work schedule, physical factors, and exposures to chemicals and x-rays, adjusted for age and parity.


      Part-time work (≤ 20 hours a week) was associated with a lower risk of preterm birth [RR, 0.7; 95% confidence interval [CI], 0.6-0.9]. Working nights was associated only with early preterm birth (< 32 weeks of gestation) (RR, 3.0; 95% CI, 1.4-6.2). Although based on only 11 exposed preterm cases, self-reported exposure to sterilizing agents was associated with an increased risk (RR, 1.9; 95% CI, 1.1-3.4).


      These data suggest that night work may be related to early but not late preterm birth, whereas physically demanding work did not strongly predict risk.

      Key words

      To read this article in full you will need to make a payment

      Purchase one-time access:

      Academic & Personal: 24 hour online accessCorporate R&D Professionals: 24 hour online access
      One-time access price info
      • For academic or personal research use, select 'Academic and Personal'
      • For corporate R&D use, select 'Corporate R&D Professionals'


      Subscribe to American Journal of Obstetrics & Gynecology
      Already a print subscriber? Claim online access
      Already an online subscriber? Sign in
      Institutional Access: Sign in to ScienceDirect


        • United States Department of Health and Human Services (US DHHS), Health Resources and Services Administration, Division of Nursing
        The national sample of registered nurses, 2000.
        United States Department of Health and Human Services, Bethesda (MD)2002
        • Vecchio D.
        • Sasco A.J.
        • Cann C.I.
        Occupational risk in health care and research.
        Am J Ind Med. 2003; 43: 369-397
        • Shortridge-McCauley L.A.
        Reproductive hazards: An overview of exposures to health care workers.
        AAOHN J. 1995; 43: 614-621
        • Figa-Talamanca I.
        Reproductive problems among women health care workers: epidemiologic evidence and preventive strategies.
        epidemiol Rev. 2000; 22: 249-260
        • Kuehn B.M.
        Groups take aim at US preterm birth rate.
        JAMA. 2006; 296: 2907-2908
        • MMWR
        Quickstats: infant mortality rates for 10 leading causes of infant death—United States.
        MMWR Wkly Rep. 2007; 56: 1115
        • Rich-Edwards J.W.
        • Goldman M.B.
        • Willett W.C.
        • et al.
        Adolescent body mass index and ovulatory infertility.
        Am J Obstet Gynecol. 1994; 171: 171-177
        • Whelan E.A.
        • Lawson C.C.
        • Grajewski B.
        • Hibert E.N.
        • Spiegelman D.
        • Rich-Edwards J.W.
        Work schedule during pregnancy and spontaneous abortion.
        Epidemiology. 2007; 18: 350-355
        • Skov T.
        • Deddens J.
        • Petersen M.R.
        • Endahl L.
        Prevalence proportion ratios: estimation and hypothesis testing.
        Int J Epidemiol. 1998; 27: 91-95
        • Spiegelman D.
        • Hertzmark E.
        Easy SAS calculations for risk or prevalence ratios and differences.
        Am J Epidemiol. 2005; 162: 199-200
        • Colditz G.A.
        • Stampfer M.
        • Willett W.C.
        • et al.
        Reproducibility and validity of self-reported menopausal status in a prospective cohort study.
        Am J Epidemiol. 1987; 126: 319-325
        • Colditz G.A.
        • Martin P.
        • Stampfer M.J.
        • et al.
        Validation of questionnaire information on risk factors and disease outcomes in a prospective cohort study of women.
        Am J Epidemiol. 1986; 123: 894-900
        • Rimm E.B.
        • Stampfer M.J.
        • Colditz G.A.
        • Chute C.G.
        • Litin L.B.
        • Willett W.C.
        Validity of self-reported waist and hip circumferences in men and women.
        Epidemiology. 1990; 1: 466-473
        • Troy L.M.
        • Hunter D.J.
        • Manson J.E.
        • Colditz G.A.
        • Stampfer M.J.
        • Willett W.C.
        The validity of recalled weight among younger women.
        Int J Obes Relat Metab Disord. 1995; 19: 570-572
        • Luke B.
        • Mamelle N.
        • Keith L.
        • et al.
        The association between occupational factors and preterm birth: a United States nurses' study.
        Am J Obstet Gynecol. 1995; 173: 849-862
      1. March of Dimes. Peristats.

        • Kramer M.S.
        The epidemiology of adverse pregnancy outcomes: an overview.
        J Nutr. 2003; 133: 1592S-1596S
        • Shennan A.H.
        • Bewley S.
        BMJ. 2006; 332: 924-925
        • Mozurkewich E.L.
        • Luke B.
        • Avni M.
        • Wolf F.M.
        Working conditions and adverse pregnancy outcome: a meta-analysis.
        Obstet Gynecol. 2000; 95: 623-635
        • Bonzini M.
        • Coggon D.
        • Palmer K.T.
        Risk of prematurity, low birthweight and pre-eclampsia in relation to working hours and physical activities: A systematic review.
        Occup Environ Med. 2007; 64: 228-243
        • Brink Henriksen T.
        • Hedegaard M.
        • Secher N.J.
        • Wilcox A.J.
        Standing at work and preterm delivery.
        Br J Obstet Gynaecol. 1995; 102: 198-206
        • Klebanoff M.A.
        • Shiono P.H.
        • Carey J.C.
        The effect of physical activity during pregnancy on preterm delivery and birth weight.
        Am J Obstet Gynecol. 1990; 163: 1450-1456
        • Launer L.J.
        • Villar J.
        • Kestler E.
        • de Onis M.
        The effect of maternal work on fetal growth and duration of pregnancy: a prospective study.
        Br J Obstet Gynaecol. 1990; 97: 62-70
        • Misra D.P.
        • Strobino D.M.
        • Stashinko E.E.
        • Nagey D.A.
        • Nanda J.
        Effects of physical activity on preterm birth.
        Am J Epidemiol. 1998; 147: 628-635
        • Newman R.B.
        • Goldenberg R.L.
        • Moawad A.H.
        • et al.
        Occupational fatigue and preterm premature rupture of membranes.
        Am J Obstet Gynecol. 2001; 184: 438-446
        • Pompeii L.A.
        • Savitz D.A.
        • Evenson K.R.
        • Rogers B.
        • McMahon M.
        Physical exertion at work and the risk of preterm delivery and small-for-gestational-age birth.
        Obstet Gynecol. 2005; 106: 1279-1288
        • Saurel-Cubizolles M.J.
        • Zeitlin J.
        • Lelong N.
        • et al.
        Employment, working conditions, and preterm birth: results from the Europrop case-control survey.
        J Epidemiol Community Health. 2004; 58: 395-401
        • Tuntiseranee P.
        • Geater A.
        • Chongsuvivatwong V.
        • Kor-anantakul O.
        The effect of heavy maternal workload on fetal growth retardation and preterm delivery: a study among Southern Thai women.
        J Occup Environ Med. 1998; 40: 1013-1021
        • Fortier I.
        • Marcoux S.
        • Brisson J.
        Maternal work during pregnancy and the risks of delivering a small-for-gestational-age or preterm infant.
        Scan J Work Environ Health. 1995; 21: 412-418
        • Ahlborg G.
        • Bodin L.
        • Hogstedt C.
        Heavy lifting during pregnancy—a hazard to the fetus?.
        Int Epidemiol Assoc. 1990; 19: 90-97
        • Hayne C.R.
        Manual transport of loads by women.
        Physiotherapy. 1981; 67: 226-231
        • Schneider K.T.
        • Huch A.
        • Huch R.
        Premature contractions: are they caused by maternal standing?.
        Acta Genet Med Gemllol. 1985; 34: 175-178
        • Bodin L.
        • Axelsson G.
        • Ahlborg Jr, G.
        The association of shift work and nitrous oxide exposure in pregnancy with birth weight and gestational age.
        Epidemiology. 1999; 10: 429-436
        • Xu X.
        • Ding M.
        • Li B.
        • Christiani D.C.
        Association of rotating shiftwork with preterm births and low birth weight among never smoking women textile workers in China.
        Occup Environ Med. 1994; 51: 470-474
        • Zhu J.L.
        • Hjollund N.H.
        • Olsen J.
        Shift work, duration of pregnancy, and birth weight: the National Birth Cohort in Denmark.
        Am J Ob Gynecol. 2004; 191: 285-291
        • Johnson J.V.
        • Lipscomb J.
        Long working hours, occupational health and the changing nature of work organization.
        Am J Ind Med. 2006; 49: 921-929
        • Caruso C.C.
        Possible broad impacts of long work hours.
        Ind Health. 2006; 44: 531-536
        • Rowland A.S.
        • Baird D.D.
        • Shore D.L.
        • Darden B.
        • Wilcox A.J.
        Ethylene oxide exposure may increase the risk of spontaneous abortion, preterm birth, and postterm birth.
        Epidemiology. 1996; 7: 363-368
        • McDiarmid M.A.
        • Condon M.
        Organizational safety culture/climate and worker compliance with hazardous drug guidelines: lessons from the blood-borne pathogen experience.
        J Occup Environ Med. 2005; 47: 740-749