Role of maternal occupational physical activity and psychosocial stressors on adverse birth outcomes

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].

Does the father's job matter? Parental occupation and preterm birth in Korea

OBJECTIVES

Limited evidence is available regarding the impact of paternal occupation and its combined effect with maternal occupation on preterm birth. Therefore, we assessed the association of maternal and paternal occupations with preterm birth.

METHODS

We used the national birth data of Korea between 2010 and 2020. Parental occupations were divided into 5 categories: (1) managers; (2) professionals, technicians, and related workers; (3) clerks and support workers; (4) service and sales workers; and (5) manual workers. A multinomial logistic regression model was used to calculate the adjusted odds ratios (aORs) of extremely, very, and moderate-to-late preterm births per occupational category considering individual risk factors.

RESULTS

For the 4,004,976 singleton births, 40.2% of mothers and 95.5% of fathers were employed. Compared to non-employment, employment was associated with a lower risk of preterm birth. Among employed mothers, service and sales occupations were associated with a higher risk of preterm birth than managerial occupations (aOR, 1.06; 95% confidence interval [CI], 1.01 to 1.10 for moderate-to-late preterm births). The father's manual occupation was associated with a higher risk of preterm birth (aOR, 1.09; 95% CI, 1.05 to 1.13 for moderate-to-late preterm) than managerial occupations. When both parents had high-risk occupations, the risk of preterm birth was higher than in cases where only the mother or neither of the parents had a high-risk occupation.

CONCLUSIONS

Paternal occupation was associated with preterm birth regardless of maternal employment and occupation and modified the effect of maternal occupation. Detailed occupational environment data are needed to identify the paternal exposures that increase the risk.

Risk Factors for Working Pregnant Women and Potential Adverse Consequences of Exposure: A Systematic Review

Objective: To assess the risk factors perceived as stressors by pregnant women in the work environment and the possible adverse consequences of such exposure for the normal development of pregnancy. Methods: Systematic review, guided by the PRISMA guidelines, and using Pubmed, Web of Science, Dialnet, SciELO, and REDIB databases. Methodological quality was assessed using the critical appraisal tools for non-randomised studies of the Joanna Briggs Institute. Results: A total of 38 studies were included. The main risk factors found in the work environment of pregnant women were chemical, psychosocial, physical-ergonomic-mechanical factors, and other work-related factors. The main adverse consequences of exposure to these factors include low birth weight, preterm birth, miscarriage, hypertension and pre-eclampsia, as well as various obstetric complications. Conclusion: During pregnancy, working conditions that are considered acceptable in normal situations may not be so during this stage due to the major changes that occur during pregnancy. Many obstetric effects may have an important impact in the mother's psychological status; therefore, it is important to optimise working conditions during this stage and to reduce or eliminate possible risks.

Amelioration of prevalence of threatened preterm labor during the COVID-19 pandemic: nationwide database analysis in Japan

We aimed to evaluate the changes in maternal and neonatal complications such as threatened preterm labor (TPL) and preterm birth before and during the coronavirus disease 2019 (COVID-19) pandemic using large-scale real-world data in Japan. We obtained data from the Japan Medical Data Center claims database and evaluated differences in maternal and neonatal complications, such as the prevalence of TPL and preterm birth before the COVID-19 pandemic (in the year 2018 or 2019) and during the COVID-19 pandemic (in 2020). We included 5533, 6257, and 5956 deliveries in the years 2018, 2019, and 2020, respectively. TPL prevalence and preterm birth had significantly decreased in 2020 (41.3%, 2.6%, respectively) compared with those reported in 2018 (45.3%, 3.9%, respectively) and 2019 (44.5%, 3.8%, respectively). Neonatal outcomes such as low-birth-weight infants and retinopathy of prematurity were also improved during the pandemic. There were no clear trends in the prevalence of maternal complications such as hypertensive disorders of pregnancy; hemolysis, elevated liver enzymes, and low platelets (HELLP) syndrome; and preeclampsia. Oral ritodrine hydrochloride usage in all participants had significantly decreased during the COVID-19 pandemic. In conclusion, our results suggest that the COVID-19 pandemic has ameliorated TPL and consequently reduced the number of preterm births.

Work stressors and coping strategies of expecting and employed women in Germany: A cross-sectional study

BACKGROUND: Research indicates pregnancy-related discrimination as a potential stressor during pregnancy for women at work, which may result in perceptions of occupational stress. OBJECTIVE: The aim of this study was to examine women’s perceptions of pregnancy-related stressors at work, problem- and emotion-focused coping strategies as well as attributed consequences for mental, physical and social dimensions. METHODS: The survey was completed online with a cross-sectional study design. Inclusion criteria for study participation were being at least 18 years old, currently pregnant and engaged in paid work (regardless of full-time or part-time work). Women were recruited via social media and with the support of pro familia. RESULTS: Results indicate that 79 (53.4%, n = 148) participating women experienced pregnancy-related stressors at work. The most relevant kinds of stressors were intrapersonal stressors and interpersonal stressors related to employers or colleagues. The most prevalent coping strategy was to seek social support or advice from gynaecologists. Attributed physical consequences were exhaustion, fatigue and sleeping disorders. Mental health consequences were named in terms of feeling emotionally upset and having fears related to the baby’s health. CONCLUSIONS: Family-friendly support policies need to be further developed and topics like pregnancy-related stressors need to be addressed in an occupational context. Especially the perspective and knowledge of employers on the topic needs to be strengthened e.g. to ensure an ongoing communication between employers, HR and employees during pregnancy. Further research is needed which provides representative data, analyses employer’s experiences and their attitudes in managing pregnancies as well as consequences for women when returning to work.

Evaluation of a pilot consultation for maternity protection at work in Switzerland

STUDY AIMS

Switzerland's Labour Law and its Ordonnance on Maternity Protection aim to protect the health of pregnant employees and their unborn children while enabling them to continue to pursue their professional activities. Some companies encounter difficulties implementing the law's provisions. The Department of Occupational and Environmental Health, part of the Center for Primary Care and Public Health (Unisanté), has provided specialist occupational medicine consultations for pregnant employees since 2015. This study aimed to evaluate how well Swiss' maternity protection legislation is implemented by examining a list of relevant indicators measured during the occupational health consultation. The study also sought to investigate the consultation support provided to the relevant stakeholders and the adjustments made to pregnant employees' working conditions.

METHODS

Descriptive variables and indicators relative to the application of the Swiss maternity protection legislation for 83 pregnant employees were collected during the consultation's pilot phase (between 2015 and 2016). Descriptive statistics and cross-analyses of these indicators were made.

RESULTS

Most pregnant employees faced multiple exposures to occupational risks. Preventive risk analyses were rare. Few adjustments to workstations were proposed. We found a tendency for employees to leave their workstations early on in their pregnancies due to sick leave certificate prescriptions. Specialist consultation and collaboration with occupational health physicians to recommend interventions for pregnant employees can provide significant benefits and help some pregnant women to continue at their workstations with appropriate adjustments.

DISCUSSION

A specialised occupational health consultation is a useful instrument for identifying occupational hazards for both the pregnant woman and her unborn child. It is also an opportunity to explain employers' legal responsibilities and obligations to safeguard the health of their pregnant employees and to give specific advice for their company's situation. This consultation also enables employers to maintain their employees' valuable professional competencies in the workplace for as long as possible. Finally, occupational health consultation helps and supports healthcare providers who must, according to the law, make decisions about whether pregnant employees can continue working safely or not.

Pre-eclampsia: a Scoping Review of Risk Factors and Suggestions for Future Research Direction

Abstract

Most of maternal deaths are preventable, and one-quarter of maternal deaths are due to pre-eclampsia and eclampsia. Prenatal screening is essential for detecting and managing pre-eclampsia. However, pre-eclampsia screening is solely based on maternal risk factors and has low (< 5% in the USA) detection rates. This review looks at pre-eclampsia from engineering, public health, and medical points of view. First, pre-eclampsia is defined clinically, and the biological basis of established risk factors is described. The multiple theories behind pre-eclampsia etiology should serve as the scientific basis behind established risk factors for pre-eclampsia; however, African American race does not have sufficient evidence as a risk factor. We then briefly describe predictive statistical models that have been created to improve screening detection rates, which use a combination of biophysical and biochemical biomarkers, as well as aspects of patient medical history as inputs. Lastly, technologies that aid in advancing pre-eclampsia screening worldwide are explored. The review concludes with suggestions for more robust pre-eclampsia research, which includes diversifying study sites, improving biomarker analytical tools, and for researchers to consider studying patients before they become pregnant to improve pre-eclampsia detection rates. Additionally, researchers must acknowledge the systemic racism involved in using race as a risk factor and include qualitative measures in study designs to capture the effects of racism on patients.

Lay Summary

Pre-eclampsia is a pregnancy-specific hypertensive disorder that can affect almost every organ system and complicates 2-8% of pregnancies globally. Here, we focus on the biological basis of the risk factors that have been identified for the condition. African American race currently does not have sufficient evidence as a risk factor and has been poorly studied. Current clinical methods poorly predict a patient's likelihood of developing pre-eclampsia; thus, researchers have made statistical models that are briefly described in this review. Then, low-cost technologies that aid in advancing pre-eclampsia screening are discussed. The review ends with suggestions for research direction to improve pre-eclampsia screening in all settings.Overall, we suggest that the future of pre-eclampsia screening should aim to identify those at risk before they become pregnant. We also suggest that the clinical standard of assessing patient risk solely on patient characteristics needs to be reevaluated, that study locations of pre-eclampsia research need to be expanded beyond a few high-income countries, and that low-cost technologies should be developed to increase access to prenatal screening.

Maternal Physical Activity at Term and Spontaneous Labor: A Case-Crossover Study

BACKGROUND

This study assessed associations between antenatal physical activity and the onset of spontaneous labor (SL).

METHODS

Data were taken from 541 participants in the third pregnancy, infection, and nutrition study who had no contraindications to antenatal physical activity. An interviewer-administered questionnaire assessed labor triggers, gestational age at birth, and physical activity within the week (24 h to 7 d) and the 24-hour period (0-24 h) prior to SL. A case-crossover design examined the association between physical activity (recreational, occupational, or any) and the risk of onset of SL within the subsequent 24 hours.

RESULTS

Overall, 21% (any), 26% (recreational), and 14% (occupational) of participants reported physical activity during the week; whereas 5% (any), 7% (recreational), and 3% (occupational) reported physical activity during the 24-hour period, prior to SL onset. Participants who reported any or occupational physical activity during the 24-hour period had a decreased likelihood of SL within the subsequent 24 hours, while participants who reported at least 30 minutes of recreational physical activity had an increased likelihood. Results remained consistent among early, full, or postterm participants.

CONCLUSION

Recreational, but not occupational, physical activity at term may increase the likelihood of SL; however, the authors cannot rule out reverse causality.

Evaluation of a blended care programme for caregivers and working pregnant women to prevent adverse pregnancy outcomes: an intervention study

Objective

Work-related activities can be a risk factor for pregnancy complications such as preterm birth. This study evaluates the effectiveness of a blended care programme, Pregnancy and Work, that provides pregnant workers and their obstetrical caregivers with advice on work adjustment.

Methods

Women less than 20 weeks of gestation, in paid employment or self-employed, in the care of four participating hospitals and their referring midwifery practices in the Netherlands received either the blended care programme (n=119), consisting of a training for professionals and a mobile health application, or care as usual (n=122) in a controlled intervention study with a follow-up in intervention and control populations. All participants completed three questionnaires concerning health and working conditions at 16, 24 and 32 weeks of pregnancy. Primary outcome was the percentage of women who received advice from their obstetrical caregiver about work adjustment. Secondary outcomes were work status, realised work adjustment and working conditions. Groups were compared using univariate and multivariate regression analyses.

Results

A total of 188 (78%) completed all three questionnaires. In the blended care group, women received more advice from obstetrical caregivers to adjust their work than in the control group, 41 (39%) vs 21 (18%) (adjusted relative risk (aRR) 2.2, 95% CI 1.4 to 3.4), but less from their employer 8 (8%) vs 31 (28%) (aRR 0.29, 95% CI 0.14 to 0.61). There were no significant differences in realised work adjustments. At 24 weeks, 30% of the pregnant women in both groups continued to work in hazardous workplaces.

Conclusion

Among working pregnant women, the blended care intervention increases advice on work adjustment given by midwives and obstetricians, but does not lead to more work adjustments.

First trimester employment, working conditions and preterm birth: a prospective population-based cohort study

Objectives

To explore the association between working conditions during first trimester and total preterm birth (PTB), and subtypes: spontaneous PTB and iatrogenic PTB, additionally to explore the role of hypertension.

Methods

Pregnant women from the Amsterdam Born Children and their Development study, filled out a questionnaire between January 2003 and March 2004, two weeks after first prenatal screening (singleton liveborn, n=7561). Working conditions were working hours/week, standing/walking hours/week, physical work load and job strain.

Results

Prolonged standing/walking during first trimester was associated with an increased risk for total PTB (OR=1.5; 95% CI 1.0–2.3, after adjustments). Other working conditions were not related to total PTB. The separation into spontaneous and iatrogenic PTB revealed that standing/walking was associated with iatrogenic PTB only (OR=2.09; 95% CI 1.00–4.97). The highest risk was found for the combination of a long workweek with high physical work load (OR=3.42; 95% CI 1.04–8.21). Hypertension did not mediate these associations; however, stratified analysis revealed that high physical work load was only related to iatrogenic PTB when pregnancy-induced hypertension was present (OR=6.44; 95% CI 1.21–29.76).

Conclusion

This study provides evidence that high physically demanding work is associated with an increased risk for iatrogenic PTB and not with spontaneous PTB. Pregnancy-induced hypertension may play a role: when present, high physical work load leads to a more severe outcome.

Development of a Comprehensive Antenatal Risk Assessment Tool to Predict Adverse Maternal and Perinatal Outcomes in Rural Areas: An Exploratory Study

Objective: To develop a comprehensive antenatal risk assessment tool to predict adverse maternal and early perinatal outcomes in a rural setting.

Materials and methods: Cross-sectional study among women admitted for delivery in a rural maternity hospital, south India. Risk factors from Rotterdam Reproductive Risk Reduction (R4U) scorecard and social factors relevant to Indian rural context were included in questionnaire. Maternal and perinatal outcomes were obtained from in-patient records. Logistic regression of risk factors associated with adverse outcomes and weighted scores assigned using beta-coefficients. Cut-off score to predict adverse outcome was derived using Receiver Operator Characteristic Curve (ROC Curve) and Likelihood ratios.

Results: Adjusted odds for adverse outcome highest for small for gestational age by ultrasound scan [OR=7.4 (1.4-36.5)], tobacco chewing [OR=5.6 (1.8–28.5)] and hypertensive disorders of pregnancy [OR=3.5 (1.9-9.6)]. After assigning weighted scores, the 74-item antenatal risk assessment tool had a maximum possible score of 86. Risk score was calculated for all subjects. Cut-off score to predict adverse outcome was 4, using ROC curve, with a sensitivity of 98%, a specificity of 21% and positive likelihood ratio of 1.23 (1.10-1.37).

Conclusion: This comprehensive antenatal risk assessment tool is easy to administer, specific to rural areas and can help community-level workers to screen, monitor, and refer high risk pregnancies for further management to prevent adverse maternal and perinatal outcomes. This may be considered a prototype towards developing more robust antenatal risk screening and outcome prediction in rural settings.

The impact of paid family leave in the United States on birth outcomes and mortality in the first year of life

OBJECTIVE

To evaluate the effect of paid family leave in California on statewide rates of preterm birth, low birthweight, postneonatal mortality, and overall infant mortality.

DATA SOURCES

Live birth and death certificates from all in-hospital deliveries occurring in California (state exposed to the family leave policy) and two unexposed states (Missouri and Pennsylvania) from 1999 to 2008 (n = 6 164 203).

STUDY DESIGN

We used a difference-in-differences approach to compare rates of infant health outcomes before and after implementation of the 2004 policy in California with rates in two states without paid family leave policies. Prespecified stratified analyses examined whether policy response differed by maternal characteristics. Conditional regression models using comparisons matched on a mother's likelihood of living in California in the pre-family leave period were then employed as sensitivity analyses to confirm our findings.

DATA COLLECTION/EXTRACTION METHODS

Probabilistic methods were used to match live birth records to maternal and newborn hospital records. Only singleton births were included. Dyads were excluded if the infant gestational age was <23 weeks or greater than 44 weeks or if the birthweight was an outlier.

PRINCIPAL FINDINGS

Compared to the unexposed states, adjusted postneonatal mortality rates decreased by 12 percent in California after 2004 (aOR 0.88, 95% CI 0.80-0.97). There were no significant effects on the other outcomes. There were no differences in the effect by race/ethnicity or insurance status except for increased odds of low birthweight among privately insured women in California after 2004. Point estimates in the propensity score-matched sensitivity models were similar to the results of the fully adjusted models for all four outcomes, but confidence intervals crossed one.

CONCLUSIONS

Implementation of paid family leave policies in California was associated with a 12 percent reduction in postneonatal mortality after adjusting for maternal and neonatal factors.

The impact of occupational activities during pregnancy on pregnancy outcomes: a systematic review and metaanalysis

OBJECTIVE

Data: An increasing number of studies suggest that exposure to physically demanding work during pregnancy could be associated with increased risks of adverse pregnancy outcomes, but the results remain conflicted and inconclusive. The purpose of this study was to examine the influence of occupational activities during pregnancy on maternal and fetal health outcomes.

STUDY

Studies of all designs (except case studies and reviews) that contained information on the relevant population (women who engaged in paid work during pregnancy), occupational exposures (heavy lifting, prolonged standing, prolonged walking, prolonged bending, and heavy physical workload), comparator (no exposure to the listed physical work demands), and outcomes (preterm birth, low birthweight, small for gestational age, miscarriage, gestational hypertension, preeclampsia, gestational diabetes mellitus, stillbirth, and intrauterine growth restriction) were included.

STUDY APPRAISAL AND SYNTHESIS METHODS

Five electronic databases and 3 gray literature sources were searched up to March 15, 2019.

RESULTS

Eighty observational studies (N=853,149) were included. Low-to-very low certainty evidence revealed that lifting objects ≥11 kg was associated with an increased odds ratio of miscarriage (odds ratio, 1.31; 95% confidence interval, 1.08-1.58; I²=79%), and preeclampsia (odds ratio, 1.35; 95% confidence interval, 1.07-1.71; I²=0%). Lifting objects for a combined weight of ≥100 kg per day was associated with an increased odds of preterm delivery (odds ratio, 1.31; 95% confidence interval, 1.11-1.56; I²=0%) and having a low birthweight neonate (odds ratio, 2.08; 95% confidence interval, 1.06-4.11; I²=73%). Prolonged standing was associated with increased odds of preterm delivery (odds ratio, 1.11; 95% confidence interval, 1.02-1.22; I²=30%) and having a small-for-gestational-age neonate (odds ratio, 1.17; 95% confidence interval, 1.01-1.35; I²=41%). A heavy physical workload was associated with increased odds of preterm delivery (odds ratio, 1.23; 95% confidence interval, 1.07-1.41; I²=32%) and having a low birthweight neonate (odds ratio, 1.79; 95% confidence interval, 1.11-2.87; I²=87%). All other associations were not statistically significant. Dose-response analysis showed women stand for >2.5 hours per day (vs no standing) had a 10% increase in the odds of having a preterm delivery.

CONCLUSION

Physically demanding work during pregnancy is associated with an increased risk of adverse pregnancy outcomes.

Maternal BMI mediates the impact of crop-related agricultural work during pregnancy on infant length in rural Pakistan: a mediation analysis of cross-sectional data

BACKGROUND

Stunted growth in early infancy is a public health problem in low-and-middle income countries. Evidence suggests heavy agricultural work during pregnancy is inversely associated with maternal body mass index (BMI) and infant birth weight in low- and middle-income countries; but pathways linking agricultural work to length-for-age Z-scores (LAZ) in early infancy have not been examined. This study aimed to investigate the relationship between agricultural work during pregnancy, post-natal maternal BMI and LAZ among young infants in rural Pakistan; and explored whether maternal BMI mediated the relationship between agricultural work and infant LAZ.

METHODS

A cross-sectional survey was conducted from December 2015 to January 2016 in rural Sindh, Pakistan. Mother-infant dyads were recruited via systematic random cluster sampling at 2-12 weeks' post-partum (n = 1161). Anthropometric measurements (maternal and infant height/length and weight) and questionnaire data were collected. Multivariable linear regression and structural-equation based mediation analyses were used to examine associations of agricultural work during pregnancy with maternal BMI and infant LAZ.

RESULTS

During pregnancy, women reported engaging in livestock-related work (57.0%), crop-related work (42.7%), and cotton harvesting (28.4%). All three forms of agricultural work were negatively associated with maternal BMI (β = - 0.67 [- 1.06; - 0.28], β = - 0.97 [- 1.51; - 0.48]; and β = - 0.87 [- 1.33; - 0.45], respectively). Maternal engagement in cotton harvesting alone was negatively associated with infant LAZ after controlling for confounding factors. The total negative effect of cotton harvesting on infant LAZ was - 0.35 [- 0.53; - 0.16]. The indirect effect of maternal BMI on infant LAZ was - 0.06 [- 0.08; - 0.03], revealing that 16% (- 0.06/- 0.35) of the relationship between cotton harvesting and infant LAZ, after adjustment, was mediated via maternal BMI.

CONCLUSION

These results underscore a need to reduce labour-intensive agricultural workload demands during pregnancy, especially in cotton harvesting, to reduce risks of negative maternal energy balance and poor growth outcomes in early infancy.

Maternal cumulative exposure to extremely low frequency electromagnetic fields, prematurity and small for gestational age: a pooled analysis of two birth cohorts

Background

Data on the effects of extremely low frequency electromagnetic fields (ELF-EMF) on pregnancy outcomes are inconclusive.

Objective

To study the relation between maternal cumulative exposure to ELF-EMF during pregnancy and the risk of prematurity or small for gestational age (SGA) in a pooled analysis of two French birth cohorts.

Methods

Elfe and Epipage2 are both population-based birth cohorts initiated in 2011 and included 18 329 and 8400 births, respectively. Health data and household, mother and child characteristics were obtained from medical records and questionnaires at maternity and during follow-up. A job exposure matrix was used to assess cumulative exposure to ELF-EMF during three periods: (1) until 15 weeks of gestation, (2) until 28 weeks of gestation and (3) until 32 weeks of gestation. Analyses were restricted to single live births in mainland France and to mothers with documented jobs (N=19 894). Adjusted logistic regression models were used.

Results

According to the period studied, 3.2%–4% of mothers were classified as highly exposed. Results were heterogeneous. Increased risks of prematurity were found among low exposed mothers for the three periods, and no association was observed among the most exposed (OR1=0.92 (95% CI 0.74 to 1.15); OR2=0.98 (95% CI 0.80 to 1.21); OR3=1.14 (95% CI 0.92 to 1.41)). For SGA, no association was observed with the exception of increased risk among the low exposed mothers in period 2 and the most exposed in period 3 (OR=1.25 (95% CI 1.02 to 1.53)).

Conclusion

Some heterogeneous associations between ELF-EMF exposure and prematurity and SGA were observed. However, due to heterogeneity (ie, their independence regarding the level of exposure), associations cannot be definitely explained by ELF-EMF exposure.

A Matched Case-Control Study on the Association Between Colds, Depressive Symptoms during Pregnancy and Congenital Heart Disease in Northwestern China

The purpose of this study was to explore the association between colds, depressive symptoms during pregnancy and offspring congenital heart disease (CHD). A 1:2 matching case-control study was conducted in Northwest China. Information was gathered by a structured questionnaire and was reviewed by investigators on the spot. Multivariate logistic regressions and nonlinear mixed effect model were performed. 614 cases and 1228 controls were available in this study. After adjusting for potential confounders, the colds during the entire pregnancy were associated with increased risk of offspring CHD (OR = 1.44(1.12-1.85)). Similarly, there was a higher depression score in CHD group than the control group (OR = 1.89(1.48-2.41)). In addition, the women with both colds and higher depression scores had a higher risk of offspring CHD (OR = 2.72(1.87-3.93)) than their counterparts with only colds (OR = 1.48(1.04-2.09)) or with only higher depression scores (OR = 1.94(1.37-2.74)). The combined effects were significant in the multiplication model (OR = 2.04(1.47-2.83)) but not in the additive model (S = 1.40(0.70-2.81), AP = 0.19(-0.15-0.53) and RERI = 0.55(-0.54-1.64)). In conclusion, the colds and depressive symptoms during pregnancy were found associated with increased risk of offspring CHD and we found for the first time that there existed a statistically multiplying interaction effect of colds and depression on increasing risk of offspring CHD.

Working conditions and absence from work during pregnancy in a cohort of healthcare workers

OBJECTIVES

To assess the relationship between exposure to occupational risk factors during pregnancy and absence from work using two different social benefits.

METHOD

Three working pregnancy trajectories (WPT) were identified in a cohort of 428 pregnant workers from a healthcare institution (period 2010-2014), based on absence days and using cluster analysis. WPT1 included absences mainly covered by sickness absence benefit (32.0% of women), WPT2 included absences covered by pregnancy occupational risk (POR) benefit (28.3%) and WPT3 were pregnant workers with few absences (39.9%). Exposure to occupational risk factors was assessed by experts and association with trajectories was analysed using logistic regression. Relative risks (RR) and their 95% CIs were adjusted for age, type of contract and shift work.

RESULTS

WPT2 was associated with exposure to physical (RR=1.86, 95%CI 1.17 to 2.97), safety (RR=2.10, 95%CI 1.61 to 2.73), ergonomic (RR=2.52, 95%CI 1.89 to 3.36) and psychosocial (RR=1.79, 95%CI 1.31 to 2.46) factors, and with exposure level. For physicians, WPT1 was associated with safety risks (RR=3.13, 95%CI 1.22 to 7.99), WPT2 with chemical and ergonomic for administrative/technical support (RR=12.20, 95%CI 1.69 to 88.09; RR=14.09, 95%CI 1.34 to 148.61, respectively), with safety and ergonomic risks for nursing aides (RR=1.84, 95%CI 1.12 to 3.02; RR=3.94, 95% CI 2.38 to 6.53, respectively), and with physical (RR=1.72, 95%CI 1.04 to 2.86), safety (RR=2.21, 95%CI 1.62 to 3.03), ergonomic (RR=2.02, 95%CI 1.44 to 2.86) and psychosocial factors (RR=1.96, 95%CI 1.32 to 2.90) for nurses.

CONCLUSIONS

Absences from work covered by POR benefit show a consistent relationship with exposure to occupational risks. Sickness absence is the most frequent benefit used by pregnant workers. Current social benefits are apparently used adequately for protecting women from occupational exposures. Future studies are needed to clarify this further.

Prenatal stress and the development of psychopathology: Lifestyle behaviors as a fundamental part of the puzzle

Maternal psychological stress, depression, and anxiety during pregnancy (prenatal stress; PNS) are thought to impact fetal development with long-term effects on offspring outcome. These effects would include physical and mental health, including psychopathology. Maternal sleep, diet, and exercise during pregnancy are lifestyle behaviors that are understudied and often solely included in PNS studies as confounders. However, there are indications that these lifestyle behaviors may actually constitute essential mediators between PNS and fetal programming processes. The goal of this theoretical review was to investigate this idea by looking at the evidence for associations between PNS and sleep, diet, and exercise, and by piecing together the information on potential underlying mechanisms and causal pathways through which these factors may affect the offspring. The analysis of the literature led to the conclusion that sleep, diet, and exercise during pregnancy, may have fundamental roles as mediators between PNS and maternal pregnancy physiology. By integrating these lifestyle behaviors into models of prenatal programming of development, a qualitatively higher and more comprehensive understanding of the prenatal origins of psychopathology can be obtained. The review finalizes by discussing some of the present challenges facing the field of PNS and offspring programming, and offering solutions for future research.

Combined exposure to lifting and psychosocial strain at work and adverse pregnancy outcomes-A study in the Danish National Birth Cohort

Background

Previous studies have investigated physical and psychosocial job exposures separately in relation to foetal growth. We therefore investigated if occupational lifting and psychosocial job strain interact to affect foetal growth and gestational length. We hypothesised that heavy lifting and high job strain would increase the risk of impacted foetal growth (small or large for gestational age) and preterm birth.

Methods

The cohort included 47,582 pregnancies from the Danish National Birth Cohort (1996–2002), where the woman was pregnant at 22 gestational weeks (GW), expected one child and worked ≥30 hours/week. Information on occupational lifting and psychosocial job strain was derived from an interview (16±3.0 GW). Data to calculate small and large for gestational age (SGA/LGA) and gestational length was retrieved from the Medical Birth Register. Interaction between lifting and job strain (Karasek’s model) was analysed by multinomial logistic regression.

Results

Overall, the adjusted regression analysis showed statistically significant interaction between lifting and job strain for SGA and LGA. For each additional 250 kg lifted/day, high strain women (high Demand/low Control) had increased odds of giving birth to a LGA-child (OR = 1.15; 95% CI 1.06–1.26), whereas women in the active group (high Demand/high Control) had increased odds of giving birth to a SGA child (OR = 1.12; 95% CI 1.03–1.23). When women lifting ≤1000 kg/day were excluded in the sensitivity analyses the interaction between lifting and job strain became insignificant. No interaction of lifting and job strain was found for gestational length.

Conclusions

The main findings may give some support to our hypothesis, as lifting in combination high with job strain increased the risk of giving birth to a LGA child. This finding was, however, not supported in the sensitivity analysis and no association of the interaction was found relative to gestational length.

Estimating the health consequences of flight attendant work: comparing flight attendant health to the general population in a cross-sectional study

BACKGROUND

Flight attendants are an understudied occupational group, despite undergoing a wide and unique range of adverse job-related exposures. In our study, we aimed to characterize the health profile of cabin crew relative to the U.S. general population.

METHODS

In 2014-2015, we surveyed participants of the Harvard Flight Attendant Health Study. We compared the prevalence of their health conditions to a contemporaneous cohort in the National Health and Nutrition Examination Survey (NHANES 2013-2014) using age-weighted standardized prevalence ratios (SPRs). We also analyzed associations between job tenure and selected health outcomes, using logistic regression and adjusting for potential confounders.

RESULTS

Compared to the NHANES population (n = 2729), flight attendants (n = 5366) had a higher prevalence of female reproductive cancers (SPR = 1.66, 95% CI: 1.18-2.33), cancers at all sites (SPR = 2.15, 95% CI: 1.73-2.67 among females), as well as sleep disorders, fatigue, and depression, with SPRs ranging between 1.98 and 5.57 depending on gender and the specific condition examined. In contrast, we observed a decreased prevalence of cardiac and respiratory outcomes among flight crew relative to NHANES. Health conditions that increased with longer job tenure were sleep disorders, anxiety/depression, alcohol abuse, any cancer, peripheral artery disease, sinusitis, foot surgery, infertility, and several perinatal outcomes.

CONCLUSIONS

We observed higher rates of specific adverse health outcomes in U.S. flight attendants compared to the general population, as well as associations between longer tenure and health conditions, which should be interpreted in light of recall bias and a cross-sectional design. Future longitudinal studies should evaluate specific exposure-disease associations among flight crew.