Menstrual Reduction With Extended Use of Combination Oral Contraceptive Pills
Bibliographic record
Abstract
In Brief OBJECTIVE To compare a traditional 28-day cycle to an extended 49-day cycle of the 30 μg ethinyl estradiol (E2)/300 μg norgestrel monophasic birth control pill regimen. METHODS Ninety subjects randomized to either 28-day cycles with 21 active pills or 49-day cycles with 42 active pills for a prospective open label trial over four 84-day reference periods or trimesters. Bleeding, pill taking, and symptom diaries were completed. The sample size with 80% power to detect a 40% reduction in bleeding days required 24 subjects in each arm. RESULTS Of the 90 women, 24 subjects (54.5%) on the 28-day cycle and 29 (63%) on the 49-day cycle completed the entire study (P = .41). There were no statistically significant differences between the two groups in demographics or continuation rates. There was a significant reduction in bleeding days in the experimental arm beginning in the first trimester (28-day = 10.9, 49-day = 6.4 mean days of bleeding, P < .001) and continuing to the fourth trimester (28-day = 11.3, 49-day = 5.8 mean days, P = .005). The number of spotting days was similar between both schedules in the first trimester (28-day = 4.8, 49-day = 3.7 mean days, P = .24) and continued into the fourth trimester (28-day = 3.4, 49-day = 2.9 mean days, P = .30). Annual expenditure for hygiene products was significantly less for extended use subjects (28-day = $41.45, 49-day = $17.54 spent, P < .001). CONCLUSION Extension of the 28-day oral contraceptive (OC) cycle to a 49-day cycle resulted in fewer bleeding days and no increase in mean spotting days or bleeding episodes. Extension of a monophasic oral contraceptive regimen from 28-day to 49-day cycles significantly decreases bleeding and hygiene product use without increased spotting.
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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 | 0.002 |
| 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 | 0.001 |
| Insufficient payload (model declined to judge) | 0.003 | 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".