Prevalence of survival without major morbidity and associated risk factors among very preterm infants: a systematic review and meta-analysis
Bibliographic record
Abstract
Introduction: Survival without major morbidity (SWMM) in very preterm infants represents a critical outcome measure in neonatal care. This systematic review evaluates both the prevalence of SWMM among infants born before 32 weeks' gestation and the associated risk factors. Methods: We conducted a comprehensive search of PubMed, Web of Science, Embase, Cochrane Library, Scopus, CNKI, CBM, and Wanfang databases from inception through February 4, 2025. Two independent reviewers performed study selection and data extraction. Study quality was assessed using the Agency for Healthcare Research and Quality (AHRQ) checklist for cross-sectional studies and the Newcastle-Ottawa Scale (NOS) for cohort studies. Pooled prevalence was calculated using a random-effects model. Heterogeneity was explored through subgroup analyses and meta-regression, and publication bias was assessed via funnel plots and further evaluated with trim-and-fill analysis. Risk factors were evaluated using multivariate meta-analysis of adjusted odds ratios (ORs) with 95% confidence intervals (CIs). Results: From 1,606 screened articles, 35 studies spanning twelve countries met inclusion criteria. The pooled SWMM incidence was 47% (95% CI: 40%-54%), with notable gestational age stratification: 67% (95% CI: 62%-72%) for infants <32 weeks vs. 44% (95% CI: 26%-61%) for those <28 weeks. Meta-analysis identified gestational age maturity (OR: 1.65; 95% CI: 1.50-1.81), antenatal corticosteroid administration (OR: 1.46; 95% CI: 1.12-1.89), and higher 5-minute Apgar scores (OR: 1.21; 95% CI: 1.06-1.37) as positive predictors of SWMM. Conversely, male sex (OR: 0.62; 95% CI: 0.55-0.71) and hemodynamically significant patent ductus arteriosus (OR: 0.51; 95% CI: 0.38-0.69) showed negative associations with SWMM. Conclusion: The review reports a 47% SWMM rate among very preterm infants, with higher rates observed in infants of later gestational age. Key predictors include gestational age, 5-minute Apgar score, and antenatal corticosteroids, while male sex and patent ductus arteriosus are associated with reduced SWMM. Limitations include heterogeneity in SWMM definitions and geographic variability. Future research should focus on standardizing outcome measures and validating risk factors through multinational studies. Systematic Review Registration: https://www.crd.york.ac.uk/PROSPERO/view/CRD42025641924, PROSPERO CRD42025641924.
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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 | 0.016 | 0.042 |
| Meta-epidemiology (narrow) | 0.003 | 0.001 |
| Meta-epidemiology (broad) | 0.022 | 0.037 |
| Bibliometrics | 0.009 | 0.009 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.004 | 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".