Influence Of Working Hours On Pregnancy Outcomes: A Systematic Review And Meta-analysis
Bibliographic record
Abstract
Approximately 90% of women remain employed during pregnancy. Long working hours have been hypothesized to be associated with an increased risk of adverse pregnancy outcomes including miscarriage and preterm delivery. PURPOSE: The purpose of this review was to evaluate the effect of long working hours (>40 hour work week) on maternal and fetal health outcomes. METHODS: Five electronic databases and two grey literature sources were searched up to March 12, 2018 and the results underwent duplicate independent screening. Studies of all designs were included (except case studies), and contained information on the Population [women who engaged in paid work during pregnancy], Exposure [>40 h work week], Comparator [working <=40 h/week], and Outcomes [preterm birth, low birthweight (birthweight<2,500g), small for gestational age, miscarriage, gestational hypertension, pre-eclampsia and intrauterine growth restriction]. Pooled odds ratio (OR) and 95% confidence interval (CI) were calculated using a random-effect, inverse variance method. Grading of Recommendations Assessment, Development and Evaluation (GRADE) framework was used to assess the quality of evidence. RESULTS: A total of 41 observational studies (N=126,632) were included. “Low” to “Very low” quality evidence from observational studies revealed that compared with normal working hours (working <=40 h/week), long working hours were associated with an increased odds of having a preterm delivery (OR: 1.16, 95% CI: 1.04, 1.3, I2=53%), a small-for-gestational age baby (OR: 1.13, 95% CI: 1.00, 1.27, I2=47%) and miscarriage (OR: 1.36, 95% CI: 1.17, 1.59, I2=47%). When meta-analysis was restricted only to adjusted ORs, long working hours were associated with an increase in risk of preterm delivery (OR: 1.18, 95% CI: 1.01, 1.37, I2=60%) and miscarriage (OR: 1.39, 95% CI: 1.09, 1.78, I2=54%). We found no significant association between long work hours and low birth weight, pre-eclampsia, gestational hypertension or intrauterine growth restriction. CONCLUSIONS: Engaging in a work week over 40 hours is associated with an increased risk of adverse pregnancy outcomes. Supported by an Occupational Health and Safety Futures Research Grant, Alberta SPOR SUPPORT Unit KT Platform and Heart & Stroke Foundation of Canada National New Investigator Award (MD).
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.012 | 0.034 |
| Meta-epidemiology (narrow) | 0.003 | 0.002 |
| Meta-epidemiology (broad) | 0.016 | 0.037 |
| Bibliometrics | 0.006 | 0.008 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.003 | 0.002 |
| Open science | 0.002 | 0.002 |
| Research integrity | 0.002 | 0.002 |
| Insufficient payload (model declined to judge) | 0.003 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".