Towards a unified perinatal theory: Reconciling the births‐based and fetus‐at‐risk models of perinatal mortality
Bibliographic record
Abstract
BACKGROUND: There is a need to reconcile the opposing perspectives of the births-based and fetuses-at-risk models of perinatal mortality and to formulate a coherent and unified perinatal theory. METHODS: Information on births in the United States from 2004 to 2015 was used to calculate gestational age-specific perinatal death rates for low- and high-risk cohorts. Cubic splines were fitted to the fetuses-at-risk birth and perinatal death rates, and first and second derivatives were estimated. Births-based perinatal death rates, and fetuses-at-risk birth and perinatal death rates and their derivatives, were examined to identify potential inter-relationships. RESULTS: The rate of change in the birth rate dictated the pattern of births-based perinatal death rates in a triphasic manner: increases in the first derivative of the birth rate at early gestation corresponded with exponential declines in perinatal death rates, the peak in the first derivative presaged the nadir in perinatal death rates, and late gestation declines in the first derivative coincided with an upturn in perinatal death rates. Late gestation increases in the first derivative of the fetuses-at-risk perinatal death rate matched the upturn in births-based perinatal death rates. Differences in birth rate acceleration/deceleration among low- and high-risk cohorts resulted in intersecting perinatal mortality curves. CONCLUSION: The first derivative of the birth rate links a cohort's fetuses-at-risk perinatal death rate to its births-based perinatal death rate, and cohort-specific differences in birth rate acceleration/deceleration are responsible for the intersecting perinatal mortality curves paradox. This mechanistic explanation unifies extant models of perinatal mortality and provides diverse insights.
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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 | 0.003 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 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 | 0.000 |
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 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".