Placenta accreta and the risk of adverse maternal and neonatal outcomes
Bibliographic record
Abstract
OBJECTIVE: Placenta accreta is an increasingly prevalent and potentially dangerous complication of pregnancy. Although most studies on the subject have addressed the risk factors for the development of this condition, evidence on maternal and neonatal outcomes for these pregnancies is scarce. The objective of the present study is to compile current evidence with regard to risk factors as well as adverse outcomes associated with placenta accreta. METHODS: We conducted a complete literature review using PubMed, MEDLINE, Cochrane Database Reviews, UptoDate, DocGuide, as well as Google scholar and textbook literature for all articles on placenta accreta, and any one of the following keywords: "risk factors", "maternal outcomes", "neonatal outcomes", "morbidity", and "mortality". Individual case reports were excluded. RESULTS: We reviewed 34 studies conducted between 1977 and 2012. A total number of 508,617 deliveries were studied, with 865 cases of confirmed placenta accreta (average pooled incidence = 1/588). The development of placenta accreta appears to be most strongly predicted by a history of cesarean section, low-lying placenta/previa, in vitro fertilization pregnancy, as well as elevated second-trimester levels of α-fetoprotein and β-human chorionic gonadotropin. The most significant maternal outcomes include the need for postpartum transfusion due to hemorrhage and peripartum hysterectomy. Maternal mortality remains rare but significantly higher than among matched, postpartum controls. Important neonatal outcomes include preterm birth, low birth weight, small for gestational age, and reduced 5-min Apgar scores. Whether the need for neonatal intensive care unit admission and steroid administration is iatrogenic and whether an increased risk of perinatal mortality is a clinically significant and independent outcome remain controversial. CONCLUSION: Although there is a significant shortage of studies on the subject, it appears that placenta accreta is associated with adverse maternal and neonatal outcomes, some of which may be life threatening. Prenatal diagnosis and adequate planning, particularly in high-risk populations, may be indicated for the reduction of these adverse outcomes.
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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 | 0.003 | 0.018 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.002 |
| Bibliometrics | 0.006 | 0.005 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.001 | 0.000 |
| 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".