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The Capital Region of Denmark - a part of Copenhagen University Hospital
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Night work and miscarriage: a Danish nationwide register-based cohort study

Research output: Contribution to journalJournal articleResearchpeer-review

  1. Night work and sick leave during pregnancy: a national register-based within-worker cohort study

    Research output: Contribution to journalJournal articleResearchpeer-review

  2. Risk of asthma and chronic obstructive pulmonary disease in a large historical cohort of Danish firefighters

    Research output: Contribution to journalJournal articleResearchpeer-review

  3. Work-unit social capital and long-term sickness absence: a prospective cohort study of 32 053 hospital employees

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  1. Early occupational intervention for people with low back pain in physically demanding jobs: A randomized clinical trial

    Research output: Contribution to journalJournal articleResearchpeer-review

  2. Forebyggelse og behandling af cytomegalovirusinfektion hos gravide og nyfødte

    Research output: Contribution to journalJournal articleResearchpeer-review

  3. Associations of different molecular forms of antimüllerian hormone and biomarkers of polycystic ovary syndrome and normal women

    Research output: Contribution to journalJournal articleResearchpeer-review

  4. Physical demand at work and sick leave due to low back pain: a cross-sectional study

    Research output: Contribution to journalJournal articleResearchpeer-review

  5. Night work during pregnancy and maternal health

    Research output: Book/ReportPh.D. thesisResearch

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OBJECTIVE: Observational studies indicate an association between working nights and miscarriage, but inaccurate exposure assessment precludes causal inference. Using payroll data with exact and prospective measurement of night work, the objective was to investigate whether working night shifts during pregnancy increases the risk of miscarriage.

METHODS: A cohort of 22 744 pregnant women was identified by linking the Danish Working Hour Database (DWHD), which holds payroll data on all Danish public hospital employees, with Danish national registers on births and admissions to hospitals (miscarriage). The risk of miscarriage during pregnancy weeks 4-22 according to measures of night work was analysed using Cox regression with time-varying exposure adjusted for a fixed set of potential confounders.

RESULTS: In total 377 896 pregnancy weeks (average 19.7) were available for follow-up. Women who had two or more night shifts the previous week had an increased risk of miscarriage after pregnancy week 8 (HR 1.32 (95% CI 1.07 to 1.62) compared with women, who did not work night shifts. The cumulated number of night shifts during pregnancy weeks 3-21 increased the risk of miscarriages in a dose-dependent pattern.

CONCLUSIONS: The study corroborates earlier findings that night work during pregnancy may confer an increased risk of miscarriage and indicates a lowest observed threshold level of two night shifts per week.

Original languageEnglish
JournalOccupational and Environmental Medicine
Pages (from-to)302-308
Number of pages7
ISSN1351-0711
DOIs
Publication statusPublished - May 2019

ID: 56914071