Advanced Maternal Age and the Risk of Cesarean Birth: A Systematic Review
Why this work is in the frame
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Bibliographic record
Abstract
BACKGROUND: The increasing pregnancy rate at advanced maternal age is contemporaneous with the increasing rate of cesarean birth. Several studies have found that advanced maternal age is a risk factor for cesarean birth. The objective of this systematic review was to assess the relationship between advanced maternal age and cesarean birth among nulliparous and multiparous women. METHODS: To identify relevant studies, we searched the literature for articles published from January 1, 1995 to March 1, 2008, using Medline, EMBASE, PsychINFO, and CINAHL. We also hand-searched the bibliographies of retrieved articles to identify additional related studies. We included all cohort studies and all case-control studies that examined this association in developed countries. The Cochrane Collaboration's Review Manager software (5.0) was used to summarize the data. RESULTS: Twenty-one studies met the inclusion criteria and were included in the review. All studies demonstrated an increased risk of cesarean birth among women at advanced maternal age compared with younger women, for both nulliparas and multiparas (relative risk varied from 1.39 to 2.76). Because we found extreme heterogeneity (both statistical and clinical) among the included studies, we did not provide a pooled estimate of the risk of cesarean birth. CONCLUSIONS: All included studies illustrated an increased risk of cesarean birth among older women. Fifteen studies adjusted this association for potential confounders, which suggests that a valid and independent association is likely to exist between advanced maternal age and cesarean birth. However, the associated factors for this increased risk are not totally understood in the literature.
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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 | 0.001 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.003 | 0.001 |
| 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 | 0.001 |
| 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 it