The effect of levonorgestrel administered in large doses at different stages of the cycle on ovarian function and endometrial morphology

Bm, Landgren; Johannisson, E.; Aedo, A.-R.; Kumar, Anil; Shi, Yong-en

doi:10.1016/0010-7824(89)90060-7

Cited by 55 publications

(34 citation statements)

References 16 publications

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“…Several research groups have set out to investigate how HEC can alter the ovulatory process, and all studies conducted to date are in agreement that there are cases in which all measured parameters were normal, alongside cases in which the LH peak was partially or totally suppressed, and in which follicle luteinization partially or totally failed to occur, depending on at which point during the menstrual cycle HEC was administered [11][12][13][14][15].…”

Section: Mechanism Of Actionmentioning

confidence: 81%

Emergency contraception: presently available formulations and controversies surrounding their use

Bastianelli

Farris

2011

Expert Review of Obstetrics & Gynecology

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Emergency contraception, or postcoital contraception, is a modality of preventing pregnancy after unprotected sexual intercourse or to avert potential contraceptive failure. The controversy revolves around the definitions of pregnancy and induced abortion. If one utilizes the medical definition accepted by the WHO, pregnancy only begins with implantation; therefore, there can be no abortion without a pregnancy and emergency contraception can in no way be equated to an abortion. The problem is that -ethically at least -there is a contention that a new human life begins right after the fertilization process is completed through full syngamy. Thus, using these parameters, it becomes vital to ascertain exactly the mechanism of action of postcoital methods. Emergency contraception exists in two different forms: the hormonal and the intrauterine. Hormonal emergency contraception was first proposed by Yuspe in the form of 100 µg ethynyl oestradiol plus 500 µg levonorgestrel taken twice at a 12-h interval. At the end of the 1900s, a second regimen -consisting of 1500 µg of levonorgestrel, within 12 h -was introduced and found in clinical trials to be more effective than the Yuspe regimen, if taken as early as possible after an unprotected intercourse. This method therefore completely replaced the Yuspe regimen in common use. Over the last 20 years, the WHO has developed a third regimen based on the use of the selective progesterone receptor modulator mifepristone; different dosages have been tested: >50, 50-25 and <10 mg, taken as a single dose, and they have been found to be equally effective, although the incidence of a delayed onset of the subsequent cycle increases with higher dosages. Two clinical studies have now compared the levonorgestrel and the mifepristone regimens; the first, conducted by WHO, compared three options: levonorgestrel, given either twice at the dose of 750 µg, or as a single 1.5-mg dose, and mifepristone, at a single dose of 10 mg. The second compared levonorgestrel (750 µg, twice) with mifepristone (10 mg, single dose). Both studies concluded that all regimens possess similar effectiveness. Recently, a new formulation consisting of a new selective progesterone receptor modulator, ulipristal acetate, has been licensed in several European countries and in the USA. At the single dose of 30 mg it shown to be a more potent inhibitor of ovulation than levonogestrel and can be effectively taken until 120 h after unprotected intercourse.

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Section: Mechanism Of Actionmentioning

confidence: 81%

Emergency contraception: presently available formulations and controversies surrounding their use

Bastianelli

Farris

2011

Expert Review of Obstetrics & Gynecology

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“…16,41,[47][48][49][50][51] However, other studies have demonstrated little to no effect on the endometrium and raise the question of whether the endometrial changes observed would be sufficient to inhibit implantation. 38,39,42,43,52,53 Other suggested mechanisms, including alteration of sperm or egg transport, interference with the fertilization process, and/or cervical mucus changes, have not been verified by clinical data. 14,40 Emergency contraception does not interrupt a pregnancy that has already implanted in the uterine lining.…”

Section: Mechanisms Of Action Of Emergency Contraceptionmentioning

confidence: 93%

“…More than 95% of these Princeton students knew about emergency contraception, but only 38% knew that the correct timing was within 72 hours of intercourse. 53 A recent survey of student health centers at universities and colleges reported that 52.2% offered emergency contraception and 47.8% did not. 91 Reasons for not offering emergency contraception at college health services included moral objections and religious affiliations, inability to prescribe or dispense, and fear of liability and concern about nonuse of traditional, regular contraceptive methods.…”

Section: Use Of Emergency Contraception On College Campusesmentioning

confidence: 98%

Emergency Contraception

2005

Pediatrics

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Teen birth rates in the United States have declined during the last decade but remain much higher than rates in other developed countries. Reduction of unintended pregnancy during adolescence and the associated negative consequences of early pregnancy and early childbearing remain public health concerns. Emergency contraception has the potential to significantly reduce teen-pregnancy rates. This policy statement provides pediatricians with a review of emergency contraception, including a definition of emergency contraception, formulations and potential adverse effects, efficacy and mechanisms of action, typical use, and safety issues, including contraindications. This review includes teens' and young adults' reported knowledge and attitudes about hormonal emergency contraception and issues of access and availability. The American Academy of Pediatrics, as well as other professional organizations, supports over-the-counter availability of emergency contraception. In previous publications, the American Academy of Pediatrics has addressed the issues of adolescent pregnancy and other methods of contraception.

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“…31,38,39 Other studies demonstrate little to no effect on the endometrium. 32,33,35,37,40,41 Suggested mechanisms, including alteration of sperm or egg transport, interference with the fertilization process, and/or cervical mucus changes, have not been verified by clinical data. 42,43 Hormonal emergency contraception does not interrupt established pregnancies and has not been linked to teratogenic effects.…”

Section: Mechanism Of Actionmentioning

confidence: 94%

“…[31][32][33][34][35][36][37] These are the same mechanisms by which other hormonal methods of contraception prevent pregnancy. Results of studies evaluating the effect of hormonal emergency contraception on the endometrium are conflicting.…”

Section: Mechanism Of Actionmentioning

confidence: 95%

Emergency Contraception

Upadhya¹,

Breuner²,

Trent³

et al. 2012

Pediatrics

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Despite significant declines over the past 2 decades, the United States continues to have teen birth rates that are significantly higher than other industrialized nations. Use of emergency contraception can reduce the risk of pregnancy if used up to 120 hours after unprotected intercourse or contraceptive failure and is most effective if used in the first 24 hours. Indications for the use of emergency contraception include sexual assault, unprotected intercourse, condom breakage or slippage, and missed or late doses of hormonal contraceptives, including the oral contraceptive pill, contraceptive patch, contraceptive ring (ie, improper placement or loss/expulsion), and injectable contraception. Adolescents younger than 17 years must obtain a prescription from a physician to access emergency contraception in most states. In all states, both males and females 17 years or older can obtain emergency contraception without a prescription. Adolescents are more likely to use emergency contraception if it has been prescribed in advance of need. The aim of this updated policy statement is to (1) educate pediatricians and other physicians on available emergency contraceptive methods; (2) provide current data on safety, efficacy, and use of emergency contraception in teenagers; and (3) encourage routine counseling and advance emergency-contraception prescription as 1 part of a public health strategy to reduce teen pregnancy. This policy focuses on pharmacologic methods of emergency contraception used within 120 hours of unprotected or underprotected coitus for the prevention of unintended pregnancy. Emergency contraceptive medications include products labeled and dedicated for use as emergency contraception by the US Food and Drug Administration (levonorgestrel and ulipristal) and the “off-label” use of combination oral contraceptives.

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The effect of levonorgestrel administered in large doses at different stages of the cycle on ovarian function and endometrial morphology

Cited by 55 publications

References 16 publications

Emergency contraception: presently available formulations and controversies surrounding their use

Emergency contraception: presently available formulations and controversies surrounding their use

Emergency Contraception

Emergency Contraception

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