Emergency contraceptives: A review of available options
Bibliographic record
Abstract
Emergency contraception is a method of contraception administered after unprotected vaginal intercourse to prevent an unplanned pregnancy. Although, emergency contraceptives (EC) have been around for at least two decades, surveys have shown there are gaps in both health professionals and women’s knowledge. Today, there are four main types of EC available: the non-hormonal copper intrauterine device, combined oral estrogen and progestin (Yuzpe regimen), oral progestin-only (levonorgestrel), and oral antiprogestin (ulipristal acetate or mifepristone). This article compares the efficacy, mechanism of action, availability and cost of these methods to help guide health professionals and patients when determining an appropriate EC. Pertinent literature was reviewed, including primary research and guidelines, to provide a current review of options. The copper intrauterine device provides the most effective form of EC and can continually be used as a regular contraceptive. Levonorgestrel (Plan B®) is widely available without a prescription and can be used up to three days after unprotected vaginal intercourse. The Yuzpe regimen is inexpensive, though it is often associated with side effects. Ulipristal acetate and mifepristone are both effective up to five days after unprotected vaginal intercourse; however, mifepristone is currently unavailable in Canada.
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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) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.002 | 0.001 |
| Bibliometrics | 0.006 | 0.005 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.002 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.010 | 0.002 |
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".