Emergency Contraception: A Last Chance to Prevent Unintended Pregnancy
Notice bibliographique
Résumé
ABSTRACT. Emergency contraception provides women with a last chance to prevent unintended pregnancy after sex. In the United States, available options for emergency contraception are three kinds of pills (levonorgestrel, ulipristal acetate, and regular oral contraceptive pills in different doses) and the copper IUD. Of these, the copper IUD is by far the most effective, followed by ulipristal acetate and levonorgestrel pills. After years of political struggle, levonorgestrel emergency contraceptive pills are now available without age or point-of-sale restrictions on store shelves. Although emergency contraceptive pills have not been shown to reduce unintended pregnancy or abortion rates at the population level, they are an important option for women who have experienced a failure of their regular method, have not used a method, or are sexually assaulted.Keywords: emergency contraception; levonorgestrel; copper IUD; contraception; postcoital contraception; morning-after pill1. IntroductionHalf of all pregnancies in the United States are unintended: 3.2 million occurred in 2006 alone, the last year for which data are available.1 Emergency contraception offers women a last chance to prevent pregnancy after unprotected intercourse. Emergency contraception is especially important for outreach to the 4.5 million women at risk of pregnancy but not using a regular method2 by providing a bridge to use of an ongoing contraceptive method. Although emergency contraceptives do not protect against sexually transmitted infection, they do offer reassurance to the 8.6 million women who rely on condoms for protection against pregnancy2 in case of condom slippage or breakage. Emergency contraceptives available in the United States include emergency contraceptive pills and the Copper T intrauterine device (IUD).3,4'52. Emergency Contraceptive PillsThere are three types of ECPs: combined ECPs containing both estrogen and progestin, progestin-only ECPs, and ECPs containing an antiprogestin (either mifepristone or ulipristal acetate). All three are available in the United States. Progestin-only ECPs have now largely replaced the older combined ECPs because they are more effective and cause fewer side effects. Although this therapy is commonly known as the morning-after pill, the term is misleading; ECPs may be initiated sooner than the morning after - immediately after unprotected intercourse - or later - for at least 120 hours after unprotected intercourse.Combined ECPs contain the hormones estrogen and progestin. The hormones that have been studied extensively in clinical trials of ECPs are the estrogen ethinyl estradiol and the progestin levonorgestrel or norgestrel (which contains two isomers, only one of which - levonorgestrel - is bioactive). One combined, dedicated (meaning it was specially packaged for use as EC) EC product (Preven) was approved by the FDA in 1998 but withdrawn from the market in 2004. This combination of active ingredients used in this way is also sometimes called the Yuzpe method, after the Canadian physician who first described the regimen. When dedicated ECPs are not available, certain ordinary birth control pills can be used in specified combinations as emergency contraception. In either case, the regimen is one dose followed by a second dose 12 hours later, where each dose consists of 1, 2, 4, 5, or 6 pills, depending on brand. Currently, 26 brands of combined oral contraceptives are approved in the United States for use as emergency contraception (see http://ec.princeton.edU/worldwide/default.asp#country).6 Research has demonstrated the safety and efficacy of an alternative regimen containing ethinyl estradiol and the progestin norethindrone;7 this result suggests that oral contraceptive pills containing progestins other than levonorgestrel may also be used for emergency contraception.Progestin-only ECPs contain no estrogen. Only the progestin levonorgestrel has been studied for freestanding use as an emergency contraceptive. …
Récupéré en direct depuis OpenAlex et désinversé. Les résumés ne sont pas conservés dans cette base de données : les index inversés représentent 8,6 Go des 9,3 Go de texte de la base, et le serveur dispose de 13 Go libres.
Comment cette classification a été obtenuedéplier
Prédiction machine sur la base complète
Imitation des enseignantsNi prévalence calibrée, ni vérité terrain. Validation humaine à venir. Le volet Gemma est une étiquette directe du modèle pour chaque travail de la base, lue sur la notice réduite au titre. Le volet Codex est un classifieur appris des 10 348 étiquettes directes de Codex et calibré sur les taux pondérés de l'échantillon; les champs sans appui suffisant ne portent aucun appel Codex. Le mode candidate est l'union des deux volets; le consensus est leur intersection. Ces sorties portent le statut machine_predicted_unvalidated et ne sont pas des étiquettes humaines.
Scores du classifieur distillé par catégorie (deux têtes)
| Catégorie | Codex | Gemma |
|---|---|---|
| Métarecherche | 0,001 | 0,004 |
| Méta-épidémiologie (sens strict) | 0,000 | 0,000 |
| Méta-épidémiologie (sens large) | 0,000 | 0,000 |
| Bibliométrie | 0,001 | 0,001 |
| Études des sciences et des technologies | 0,001 | 0,001 |
| Communication savante | 0,002 | 0,001 |
| Science ouverte | 0,001 | 0,001 |
| Intégrité de la recherche | 0,002 | 0,003 |
| Charge utile insuffisante (le modèle a refusé de juger) | 0,032 | 0,007 |
Scores machine (provisoires)
Les deux têtes enseignantes du modèle étudiant, lues sur ce travail. Un score ordonne la base pour la relecture; il n'affirme jamais une catégorie, et le statut de validation accompagne chaque rangée tel quel.
Scores de référence d'un modèle non mature (critères de maturité non atteints, 7 itérations). Un score ordonne; il n'affirme jamais une catégorie.
score_only:v0-immature-baseline · tel quel depuis la passe de notation : score_only signifie que le nombre peut ordonner les travaux, et qu'aucune étiquette de catégorie n'en découleClassification
machine, non validéePrédiction automatique; un appel candidat d’une seule source (Gemma direct ou Codex distillé), pas un consensus.
Le détail, modèle par modèle et score par score, se trouve en fin de page sous « Comment cette classification a été obtenue ».