Anal incontinence following obstetric anal sphincter injury: Is there a difference between subtypes? A systematic review
Bibliographic record
Abstract
AIMS: Obstetric anal sphincter injury (OASI) is associated with long-term anal incontinence (AI). We aimed to address the following questions: (a) are women with major OASI (grade 3c and 4) at higher risk of developing AI when compared to women with minor OASI (grade 3a and 3b)? (b) is a fourth-degree tear more likely to cause AI over a third-degree tear? METHODS: A systematic literature search from inception until September 2022. We considered prospective and retrospective cohort studies, cross-sectional and case-control studies without language restrictions. The quality was assessed by the Newcastle-Ottawa Scale and the Joanna Briggs Institute critical appraisal checklist. Risk ratios (RRs) were calculated to measure the effect of different grades of OASI. RESULTS: Out of 22 studies, 8 were prospective cohort, 8 were retrospective cohort, and 6 were cross-sectional studies. Length of follow-up ranged from 1 month to 23 years, with the majority of the reports (n = 16) analysing data within 12-months postpartum. Third-degree tears evaluated were 6454 versus 764 fourth-degree tears. The risk of bias was low in 3, medium in 14 and high in 5 studies, respectively. Prospective studies showed that major tears are associated with a twofold risk of AI for major tears versus minor tears, while retrospective studies consistently showed a risk of fecal incontinence (FI) which was two- to fourfold higher. Prospective studies showed a trend toward worsening AI symptoms for fourth-degree tears, but this failed to reach statistical significance. Cross-sectional studies with long-term (≥5 years) follow-up showed that women with fourth-degree tear were more likely to develop AI, with an RR ranging from 1.4 to 2.2. Out of 3, 2 retrospective studies showed similar findings, but the follow-up was significantly shorter (≤1 year). Contrasting results were noted for FI rates, as only 5 out of 10 studies supported an association between fourth-degree tear and FI. CONCLUSIONS: Most studies investigate bowel symptoms within few months from delivery. Data heterogeneity hindered a meaningful synthesis. Prospective cohort studies with adequate power and long-term follow-up should be performed to evaluate the risk of AI for each OASI subtype.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
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 | 0.000 | 0.001 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.005 | 0.001 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.001 | 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 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".