OC05.08: Perinatal outcome and prognostic factors of fetal megacystis diagnosed at 11 to 14 weeks of gestation
Bibliographic record
Abstract
This study aims to evaluate the perinatal outcomes and predictive factors of adverse obstetrical outcomes following a diagnosis of fetal megacystis in the first trimester, defined as longitudinal bladder diameter (LBD) of 7 mm or greater at 11-14 week's gestation. This was a retrospective review at a tertiary centre from January 1, 2010 to January 1, 2020. Maternal characteristics, ultrasound findings, pregnancy outcomes, autopsy reports, and genetic testing results are collected from patient charts and electronic databases. Among 97 fetuses, 54% resulted in live births and 46% ended in fetal loss including intrauterine demise or elective termination. The incidence of aneuploidy was 12%. Pathological diagnoses were achievable in 32 cases (12 aneuploidy, 11 obstructive uropathy, 3 caudal regression syndrome, 3 cloacal anomalies, 1 Beckwith-Wiedemann syndrome, 1 pentalogy of Cantrell, 1 Twin–twin transfusion syndrome). Among the livebirths, additional extra-renal abnormalities were detected in only 1 fetus and megacystis spontaneously resolved in 96%. However, the two cases where fetal megacystis did not resolve had major postnatal diagnosis (1 complex cloacal abnormalities, 1 megacystis-microcolon-intestinal-hypoperistalsis syndrome). SROC analysis demonstrated that LBD was the best single predictor of adverse outcome with LBD ≥ 12 mm as the optimal cut-point (sensitivity 67%, specificity 88%). Using the threshold of LBD < 12 mm, the prevalence of aneuploidy was similar between the groups, but there were no “missed” cases of lower urinary tract obstruction in fetuses with LBD < 12 mm vs. 11 cases (30.6%) among those with LBD ≥ 12 mm. All women diagnosed with fetal megacystis in the first trimester should be offered prenatal testing to rule out aneuploidy. Positive prognostic factors include LBD < 12 mm, normal karyotypes, and spontaneous resolution of megacystis.
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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) | 0.000 | 0.000 |
| Bibliometrics | 0.002 | 0.002 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.000 |
| 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".