Consistency of endothelial function across two consecutive oral contraceptive pill cycles
Bibliographic record
Abstract
Oral contraceptive pills (OCPs), composed of an active pill (AP; synthetic hormone) and a placebo pill (PP; synthetic hormone-free) phase, might impact endothelial function across the OCP cycle depending on the synthetic hormone composition (type and dose). Only one study has investigated very low-dose second-generation OCP users, finding impaired endothelial function in the AP versus PP phase. No studies have reported individual changes in endothelial function across OCP phases, and no studies have examined repeatability of endothelial function across multiple OCP cycles. Owing to the consistency of synthetic hormone exposure in OCP users, we hypothesized that group and individual flow-mediated dilatation (FMD) responses to the OCP phase would be consistent across two OCP cycles. Endothelial function was assessed by FMD via Duplex ultrasound in 17 very low-dose second-generation OCP users (19 ± 2 years of age) during the AP phase and PP phase for two consecutive OCP cycles. Individual responses were classified using a threshold of ±2 × typical error. There was a main effect of phase such that FMD was lower in the AP versus PP phase (P = 0.022; AP = 4.3% ± 1.3%, PP = 5.4% ± 1.4%). Threshold analysis revealed no consistent responders, and there was no relationship between Δ%FMD in cycle 1 and cycle 2 (P = 0.220; r = -0.314). Overall, these results suggest that exposure to the synthetic hormones in second-generation OCPs might be detrimental to vascular function, although this was not demonstrated to be a consistent trait-like response at the individual level over two cycles.
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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 | 0.001 | 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) | 0.001 | 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".