Maternal Cell Contamination of Amniotic Fluid Samples Obtained by Open Needle Versus Trocar Technique of Amniocentesis
Bibliographic record
Abstract
OBJECTIVE: To determine the incidence of maternal cell contamination (MCC) in the open-needle amniocentesis sampling technique compared with the trocar-in-place technique. METHODS: A retrospective analysis was conducted on 2,498 mid-trimester amniocenteses performed in two tertiary care centres in Canada. The University of Alberta centre used the open-needle (without the trocar) technique and the University of British Columbia centre used the standard (with the trocar in place) technique. Data were gathered regarding the nature of the amniotic fluid, number of needle passes, amniocentesis results, and the occurrence of maternal cell contamination. The statistical analysis used logistic regression, and controlled for the potential confounders of bloody fluid taps and requirement for more than one needle insertion. RESULTS: The incidence of maternal cell contamination was 1.16% with the open-needle technique and 0.78% with the standard trocar-in-place technique (p < 0.315), with a power of 42%. CONCLUSION: The data suggested there is no significant increase in maternal cell contamination with the open-needle versus trocar-in-place techniques of amniocentesis. However, the small sample size, combined with the low prevalence of the outcome of interest (MCC), provides insufficient power to draw firm conclusions about the difference in MCC between the two techniques.
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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 | 0.000 | 0.003 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| 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".