Perinatal Outcomes of Normal Cotwins in Twin Pregnancies with One Structurally Anomalous Fetus: A Population-Based Retrospective Study
Bibliographic record
Abstract
We examined the impact of the presence of one anomalous fetus in a twin pregnancy on perinatal outcomes in the normal cotwin. Perinatal outcomes in cotwins with an anomalous twin and cotwins without an anomalous twin were compared using data from the 1995 to 1997 United States Matched Multiple Births dataset. The two groups were matched by maternal age, parity, birth order, gender, and sex concordance (1:4 matching). The risks of preterm birth, low birth weight, small-for-gestational-age birth, fetal distress, the use of assisted ventilation, low Apgar score, fetal death, neonatal death, and infant death in the 3307 normal cotwins with a twin affected by structural anomalies were significantly higher than those of the 12,813 matched cotwins without an anomalous twin. The presence of one structurally anomalous fetus in a twin pregnancy increases the risks of adverse perinatal outcomes in the cotwin without a fetal anomaly.
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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 | 0.001 | 0.004 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.001 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 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".