Effect of maternal smoking on prenatal screening for Down syndrome and trisomy 18 in the first trimester of pregnancy
Bibliographic record
Abstract
OBJECTIVES: To assess the impact of maternal smoking on first-trimester prenatal screening results for Down syndrome and trisomy 18. METHODS: Data on maternal smoking status, maternal age, gestational dating, levels of free beta-human chorionic gonadotrophin (beta-hCG) and pregnancy-associated plasma protein A (PAPP-A) in maternal blood and fetal nuchal translucency (NT) thickness were analyzed from a cohort of 53 114 women. Statistical analyses were carried out for crude and adjusted comparisons between smoking and nonsmoking groups. RESULTS: In women who smoked during the first trimester of pregnancy, PAPP-A and free beta-hCG levels from dried blood were significantly decreased (p < 0.001) and fetal NT thickness was significantly increased (p < 0.001). For an overall risk assessment combining maternal age and biochemical and ultrasound markers, no significant changes for Down syndrome were found with smoking, but significant increases in average risk as well as in positive rates were found for trisomy 18 (p < 0.001). A potential association between maternal smoking and trisomy 18 remains to be clarified. CONCLUSION: Adjustment for smoking is recommended in first-trimester prenatal screening for trisomy 18 and probably not warranted for Down syndrome because of the cancelling effects of decreased free beta-hCG and increased NT. Further research is required to demonstrate a biological association between maternal smoking and trisomy 18.
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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 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 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".