Second trimester prenatal screening for Down syndrome: the associations between the levels of serum markers in successive pregnancies
Bibliographic record
Abstract
OBJECTIVE: To investigate the association of Down syndrome screening results in successive pregnancies, and assess the impacts of including previous screening results in the current risk estimation on screening performance. METHODS: The study was based on 56,951 women who had triple marker screening in two or more singleton pregnancies in the Ontario Maternal Serum Screening (MSS) program between October 1993 and September 2000. The problem of recurrent false positive results was examined by comparing screening results from different pregnancies in the same individuals. Between-pregnancy associations in the levels of serum markers were estimated using correlation analysis. A published method was used to adjust current risk estimation for previous screening results. The effect of this adjustment was assessed by comparing screening performances prior and subsequent to the adjustment. RESULTS: The observed false positive rate (FPR) in subsequent pregnancies was 2.5 times higher than that expected (26.4% vs 10.7%) among women who screened positive in one previous pregnancy, and 3.9 times higher (47.4% vs 12.1%) among women who screened positive in two previous pregnancies. Adjusting for a previous screening result will significantly reduce the recurrent FPR without compromising detection. CONCLUSION: Risk estimation for Down syndrome may be adjusted using the screening result from a previous pregnancy.
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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 | 0.001 | 0.003 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| 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".