Shift and night work during pregnancy and preterm birth-a cohort study of Swedish health care employees

Consensus-Driven Recommendations to Support Physician Pregnancy, Adoption, Surrogacy, Parental Leave, and Lactation in Emergency Medicine

The emergency department clinical environment is unique, and guidelines for promoting supportive and equitable workplace cultures ensure success and longevity for pregnant persons and parents in emergency medicine. There is paucity, variability, and dissatisfaction with current parental (historically referred to as maternity and paternity) leave policies. This paper describes the development of consensus-derived recommendations to serve as a framework for emergency departments across the country for incorporating family-friendly policies. Policies that foster a family-inclusive workplace by allowing for professional advancement without sacrificing personal values regardless of sex, gender, and gender identity are critical for emergency medicine recruitment and retention.

Associations of Night Shift Status During Pregnancy With Small for Gestational Age and Preterm Births

BACKGROUND

Shift work, including night shift work, during pregnancy has been associated with adverse birth outcomes such as small for gestational age (SGA) infants and preterm births. This study, conducted in South Korea using the Korean CHildren's ENvironmental health Study (Ko-CHENS) cohort, aimed to investigate the association between shift work and night shift status during pregnancy and adverse birth outcomes.

METHODS

The Korean Ko-CHENS is a nationwide prospective birth cohort study of children's environmental diseases, conducted by the Ministry of Environment and the National Institute of Environmental Research. This study included pregnant women recruited from 2015 to 2020 for Ko-CHENS Core Cohorts, and 4,944 out of a total of 5,213 pregnant women were selected as final subjects. A logistic regression model was used to identify the risk factors affecting SGA births, preterm births, and low-birth-weight infants, and the odds ratio (OR) was adjusted. This was confirmed by calculating ORs. Maternal age, infant sex, maternal educational status, body mass index, smoking status, alcohol consumption status, parity, gestational diabetes mellitus, preeclampsia, and abortion history were used as adjusted variables.

RESULTS

No statistically significant differences were observed in the birth outcomes or maternal working patterns. There were no significant differences in the adjusted odds ratios (aORs) of SGA and preterm births between the non-worker, day worker, and shift worker. However, there was a significant difference in the aORs of SGA between non-workers and night shift workers. (aORs [95% confidence interval], 2.643 [1.193-5.859]).

CONCLUSION

Working during pregnancy did not increase the risk of SGA or preterm birth, and night shift work did not increase the risk of preterm birth. However, night-shift work increases the risk of SGA.

Shift work and menstruation: A meta-analysis study

Background

Shift work is a potential risk factor for women's reproductive health. Evidence suggests that shift work is associated with menstrual disorders, reproductive disturbances, and adverse pregnancy outcomes. However, previous studies did not systematically examine the results of menstrual irregularities, dysmenorrhea, and early menopause at the same time.

Objective

To determine the relationship between shift work and women's menstrual characteristics (e.g., irregular menstruation, dysmenorrhea, and early menopause).

Methods

Four databases (PubMed, Embase, Cochrane, and Web of Science) were searched up to December 2022. The study characteristics and risk assessment values of the literature were extracted from 21 studies that met the criteria. Odds ratios (ORs), relative risks (RRs), hazard ratios (HRs), and 95% confidence intervals (CIs) were calculated to assess the relationship between shift work exposure and menstruation. The included studies were evaluated for heterogeneity, publication bias, sensitivity analysis, and subgroup analysis.

Results

A total of 21 studies with 195,538 female participants, including 16 cross-sectional studies and 5 cohort studies, were included in this meta-analysis. According to the quality evaluation, the included research had high methodological quality. The overall ORs of shift work for the likelihood of irregular menstruation and dysmenorrhea were 1.30 (95% CI, 1.23-1.36) (I2 = 41.9%, P < 0.05) and 1.35 (95% CI, 1.04-1.75) (I2 = 73.0%, P < 0.05), respectively. There was a significant positive association between shift work and the risk of early menopause (HR = 1.09, 95% CI, 1.04-1.14), without significant heterogeneity (I2 = 0.0%, P > 0.05).

Conclusions

This meta-analysis indicated that shift workers have significantly higher odds of menstrual disorders, dysmenorrhea, and early menopause. This study focuses on female reproductive health and has broad implications for adjusting optimal working hours and shift schedules for female workers.

Night work during pregnancy and small for gestational age: a Danish nationwide register-based cohort study

OBJECTIVE

The aim was to investigate the association between night work during pregnancy and risk of having a small for gestational age (SGA) child.

METHODS

This cohort study had payroll data with detailed information on working hours for employees in all Danish administrative regions (primarily hospital employees) between 2007 and 2015, retrieved from the Danish Working Hour Database. Pregnancies, covariates and outcome were identified from the national birth registry. We used logistic regression to investigate the association between intensity and duration of night work during the first 32 pregnancy weeks and SGA. The adjusted model included age, body mass index, socioeconomic status and smoking. Using quantitative bias analysis and G-estimation, we explored potential healthy worker survivor bias (HWSB).

RESULTS

The final cohort comprised 24 548 singleton pregnancies in 19 107 women, primarily nurses and medical doctors. None of the dimensions of night work were associated with an increased risk of SGA. We found a tendency towards higher risk of SGA in pregnancies where the women stopped having night shifts during pregnancy. Using G-estimation we found an OR<1 for the association between night work and SGA if all workers continued having night work during pregnancy compared with daywork only.

CONCLUSION

We found no increased risk of SGA in association with night work during pregnancy among healthcare workers. G-estimation was not precise enough to estimate the observed indication of HWSB. We need better data on pregnancy discomforts and complications to be able to safely rule out HWSB.

Maternal Occupational Risk Factors and Preterm Birth: A Systematic Review and Meta-Analysis

Objective: This systematic review and meta-analysis aimed to summarize the evidence on the relationship between physical occupational risks (high physical workload, long working hours, shift work, whole-body vibrations, prolonged standing, and heavy lifting) and preterm birth. Methods: A systematic review and meta-analysis was conducted across six databases to investigate the relationship between physical occupational risks and preterm birth. Result: A comprehensive analysis of 37 studies with varying sample sizes found moderate evidence of positive associations between high physical workload, long working hours, shift work, whole-body vibration, and preterm birth. Meta-analysis showed a 44% higher risk (OR 1.44, 95% CI 1.25-1.66) for preterm birth with long working hours and a 63% higher risk (OR 1.63, 95% CI 1.03-2.58) with shift work. Conclusion: Pregnant women in physically demanding jobs, those working long hours or on shifts, and those exposed to whole-body vibration have an increased risk of preterm birth. Employers should establish supportive workplaces, policymakers implement protective measures, healthcare providers conduct screenings, and pregnant women must stay informed and mitigate these job-related risks. Systematic Review Registration: [https://www.crd.york.ac.uk/prospero/], Identifier [CRD42022357045].

Pregnant nurses' experiences of working shifts: a qualitative systematic review

OBJECTIVE

The objective of this systematic review was to synthesize the experiences of nurses who work shifts during pregnancy.

INCLUSION CRITERIA

This review included studies that focused on the experiences of pregnant registered nurses, regardless of their level of qualification, working shifts in any workplace, including hospitals, nursing home facilities, or clinics, in any country. Nurses not involved in direct care (eg, advanced practice nurses, administrators, educators) were excluded.

METHODS

The review followed the JBI methodology for qualitative systematic reviews. Published and gray literature were searched for via CINAHL (EBSCOhost), MEDLINE (EBSCOhost), PsycINFO (EBSCOhost), Igaku Chuo Zasshi (Japan Medical Abstracts Society), and JBI Evidence Synthesis. No language restrictions were imposed, and the date limit was set for 2013 to 2021. Two independent reviewers performed data collection, extraction, critical appraisal, and analysis. Unequivocal and credible findings were used to develop categories, which were then synthesized to provide a set of comprehensive findings, which were graded according to ConQual.

RESULTS

Five qualitative studies were included (2 from the USA, 2 from Japan, and 1 from Korea), from which 23 findings with narrative illustrations were extracted. Of these findings, 22 were assessed as unequivocal, 1 as credible, and 3 not supported. The studies were low-to-moderate quality based on the JBI critical appraisal checklist for qualitative research. All studies used qualitative methodologies, including phenomenology, qualitative description, and the grounded theory approach. Results were integrated into 7 categories and 3 synthesized findings. The first synthesized finding was that nurses struggle with the physical burden of pregnancy and work environments that threaten continued pregnancy. The second was that nurses achieve work-pregnancy compatibility by disclosing their pregnancy and obtaining support. The third was that development as a nurse results from continuing to work during pregnancy.

CONCLUSIONS

Pregnant nurses face a harsh work environment; the support they receive after disclosing their pregnancy allows them to balance work and pregnancy; and they feel that they grow as professionals by continuing to work even if they are pregnant. More research is needed to inform support systems for them.

REVIEW REGISTRATION

PROSPERO CRD42022309674.

SUPPLEMENTAL DIGITAL CONTENT

A Japanese-language version of the abstract of this review is available [http://links.lww.com/SRX/A31].

Night and shift work patterns and incidence of type 2 diabetes and hypertension in a prospective cohort study of healthcare employees

OBJECTIVES

This study aimed to evaluate effects of night and shift work patterns on type 2 diabetes (T2D) and hypertension in a longitudinal study, with detailed information on working hours.

METHODS

The cohort comprised about 28 000 nurses and nursing assistants employed for more than one year 2008-2016 in Stockholm, Sweden. The employee register held detailed individual information on daily working hours. Information on diagnoses came from national and regional registers. Hazard ratios (HR) and confidence intervals (CI) were estimated by discrete-time proportional hazard models, adjusting for sex, age, country of birth, and profession.

RESULTS

During follow-up in 2013-2017, we identified 232 cases of T2D and 875 of hypertension. We observed an increased risk of T2D, but not hypertension, among employees who worked only night shifts the previous year (HR 1.59, 95% CI 1.02-2.43) and those with intensive shift work (>120 afternoon and/or night shifts the previous year: HR 1.67, 95% CI 1.11-2.48) compared to only day work. There was a non-significantly increased risk of T2D related to mixed day and afternoon shifts (HR 1.34, 95% CI 0.97-1.88). We observed tendencies in increased risk of T2D related to frequent spells of ≥3 consecutive night shifts and with number of years with exclusive (but not mixed) night work.

CONCLUSIONS

Permanent night work and frequent afternoon and/or night shifts were associated with an increased risk of T2D the following year, but not hypertension. The T2D risk was, to some extent, affected by frequent spells of several night shifts in a row and by cumulative years with permanent night work.

Association of working hours and cumulative fatigue among Chinese primary health care professionals

Introduction

The association between long working hours and cumulative fatigue is widely acknowledged in the literature. However, there are few studies on the mediating effect of working hours on cumulative fatigue using occupational stress as a mediating variable. The present study aimed at investigating the mediating role of occupational stress in the relationship between working hours and cumulative fatigue in a sample of 1,327 primary health care professionals.

Methods

The Core Occupational Stress Scale and the Workers' Fatigue Accumulation Self-Diagnosis Scale were utilized in this study. The mediating effect of occupational stress was examined using hierarchical regression analysis and the Bootstrap test.

Results

Working hours were positively associated with cumulative fatigue via occupational stress (p < 0.01). Occupational stress was found to partially mediate the relationship between working hours and cumulative fatigue, with a mediating effect of 0.078 (95% CI: 0.043-0.115, p < 0.01), and the percentage of occupational stress mediating effect was 28.3%.

Discussion

Working hours can be associated with cumulative fatigue either directly or indirectly via occupational stress. As a result, by reducing occupational stress, primary health care professionals may reduce the cumulative fatigue symptoms caused by long hours of work.

Advances in circadian clock regulation of reproduction

The mammalian circadian clock is an endogenously regulated oscillator that is synchronized with solar time and cycle within a 24-h period. The circadian clock exists not only in the suprachiasmatic nucleus (SCN) of the hypothalamus, a central pacemaker of the circadian clock system, but also in numerous peripheral tissues known as peripheral circadian oscillators. The SCN and peripheral circadian oscillators mutually orchestrate the diurnal rhythms of various physiological and behavioral processes in a hierarchical manner. In the past two decades, peripheral circadian oscillators have been identified and their function has been determined in the mammalian reproductive system and its related endocrine glands, including the hypothalamus, pituitary gland, ovaries, testes, uterus, mammary glands, and prostate gland. Increasing evidence indicates that both the SCN and peripheral circadian oscillators play discrete roles in coordinating reproductive processes and optimizing fertility in mammals. The present study reviews recent evidence on circadian clock regulation of reproductive function in the hypothalamic-pituitary-gonadal axis and reproductive system. Additionally, we elucidate the effects of chronodisruption (as a result of, for example, shift work, jet lag, disrupted eating patterns, and sleep disorders) on mammalian reproductive performance from multiple aspects. Finally, we propose potential behavioral changes or pharmaceutical strategies for the prevention and treatment of reproductive disorders from the perspective of chronomedicine. Conclusively, this review will outline recent evidence on circadian clock regulation of reproduction, providing novel perspectives on the role of the circadian clock in maintaining normal reproductive functions and in diseases that negatively affect fertility.

Sick leave during pregnancy and occupational factors: a systematic review

BACKGROUND

The reported prevalence of sick leave (SL) during pregnancy is high among European pregnant workers (PW). The causes of SL during pregnancy are complex, and further research is necessary to explain their occurrence.

AIMS

Summarize the evidence for an association between occupational risks for pregnancy and SL.

METHODS

A systematic review was conducted by two independent reviewers using PRISMA guidelines. Two databases (Pubmed, Embase) were interrogated between January 1990 and November 2021. The search question integrated key terms according to the PICOS acronym (free terms, MeSH, EMTREE). The quality of the selected studies was assessed according to the Methodological Index for Non-randomized Studies score.

RESULTS

This review assessed 11 epidemiological studies. Overall, the mean Methodological Index for Non-Randomized Studies score was 11, indicating moderate study quality. The results of the limited number of studies showed limited evidence for associations between psychosocial and physical work-related risk factors and the occurrence of SL among PW. However, this assessment was strengthened by the observation in several studies of a dose-response relationship between the number of occupational risks during pregnancy and SL.

CONCLUSIONS

The analysis of this review implicates PW'S exposure to occupational risks in the occurrence of SL. However, the few studies that support this conclusion have provided weak evidence; thus, further research is necessary.

Night and shift work characteristics and incident ischemic heart disease and atrial fibrillation among healthcare employees - a prospective cohort study

OBJECTIVE

This study aimed to examine the effects of various aspects of night and shift work on the risk of incident ischemic heart disease (IHD) and atrial fibrillation (AF) using detailed and registry-based exposure data.

METHODS

This prospective cohort study included >30 300 healthcare employees (eg, nurses, nursing assistants) employed for at least one year in Region Stockholm 2008-2016. Information on daily working hours was obtained from a computerized administrative employee register and outcomes from national and regional registers. Using discrete-time proportional hazard models, we analyzed the outcomes as functions of working hour characteristics the preceding year, adjusted for sex, age, country of birth, education, and profession.

RESULTS

We observed 223 cases of IHD and 281 cases of AF during follow-up 2009-2016. The risk of IHD was increased among employees who the preceding year had permanent night shifts compared to those with permanent day work [hazard ratio (HR) 1.61, 95% confidence interval (CI) 1.06-2.43] and among employees working night shifts >120 times per year compared to those who never worked night (HR 1.53, 95% CI 1.05-2.21). When restricted to non-night workers, the risk of IHD was increased for employees having frequent quick returns from afternoon shifts. No increased risks were observed for AF.

CONCLUSIONS

Night work, especially working permanent night shifts and frequent night shifts, is associated with an increased risk of incident IHD but not AF. Moreover, frequent quick returns from afternoon shifts (among non-night workers) increased IHD risk. Organizing work schedules to minimize these exposures may reduce IHD risk.