Physical Exertion Immediately Before Early Preterm Delivery
Bibliographic record
Abstract
BACKGROUND: Occupational exertion is associated with a higher risk of preterm delivery, although studies of leisure time activities generally document reduced risks. Less is known about the risk of preterm delivery immediately following episodes of moderate or heavy physical exertion. METHODS: We conducted a case-crossover study of 722 women interviewed during their hospital stay for early preterm delivery, defined by a gestational age before 34 weeks, and after 20 weeks. Interviews occurred between March 2013 and December 2015 in seven hospitals in Lima, Peru. RESULTS: The incidence rate ratio (RR) of early preterm delivery was 5.82-fold higher (95% confidence interval [CI] = 4.29, 7.36) in the hour following moderate or heavy physical exertion compared with other times and returned to baseline in the hours thereafter. The RR of early preterm delivery within an hour of physical exertion was lower for exertion at moderate intensity (RR = 2.43; 95% CI = 1.50, 3.96) than at heavy intensity (RR = 23.62; 95% CI = 15.54, 35.91; P-homogeneity < 0.001). The RR of early preterm delivery was lower in the hour following moderate physical exertion among women who habitually engaged in physical exertion >3 times per week in the year before pregnancy (RR = 1.56; 95% CI = 0.81, 3.00) compared with more sedentary women (RR = 6.91; 95% CI = 3.20, 14.92; P-homogeneity = 0.003). CONCLUSIONS: Our study showed a heightened risk of early preterm delivery in the hour following moderate or heavy physical exertion.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 0.002 |
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 teacher head, 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".