On the mechanisms of action of short-term levonorgestrel administration in emergency contraception

Durand, Marjorie; Cravioto, Ma del Carmen; Raymond, Elizabeth G.; Durán-Sánchez, Ofelia; Cruz-Hinojosa, Ma De la Luz; Castell-Rodrı́guez, Andrés; Schiavon, Raffaela; Larrea, Fernando

doi:10.1016/s0010-7824(01)00250-5

Cited by 173 publications

(152 citation statements)

References 40 publications

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“…It has been established that LNG has no effect if administered immediately before ovulation, and it is also considered to be ineffective after fertilization (10). Clinical trials confirmed that LNG does not influence the process of implantation of the embryo in the endometrium, nor has any significant effect been noted on oviduct motility (11).…”

Section: Levonorgrestrelmentioning

confidence: 99%

Mechanism of Action, Efficacy and Safety of Emergency Hormonal Contraception (levonorgestrel and ulipristal acetate) and Attitudes of Pharmacists

Milosavljevic¹,

Ilić²,

Krajnović³

2014

Acta Facultatis Medicae Naissensis

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ACTA FACULTATIS MEDICAE NAISSENSISUDC: 615.256.5.03 S U M M A R YEmergency hormonal contraception is used to prevent unintended pregnancy postcoitally. The mechanism of action of the most frequently used hormonal preparations for emergency contraception, levonorgestrel (LNG) and ulipristal acetate (UPA), is still not fully known, but clinical trials indicate that they act by inhibiting or delaying ovulation. LNG has a long history of use for emergency contraception, proven safety and high efficacy if administered in the preovulation period. The newest emergency contraceptive, UPA, available only with a prescription, is indicated within this period of 120 hours after sexual intercourse and the data indicate that UPA does not lose efficacy within this period. Clinical trials showed its noninferiority versus LNG and its effect on the potentially occurring pregnancy is being additionally monitored. However, many misconceptions and controversial opinions about emergency contraception are still present, even among pharmacists. A search of Medline database identified 20 papers published from January 1993 to December 2012, on pharmacists' knowledge, attitudes and practices related to emergency contraception. In these papers, the attitudes of pharmacists pertaining to the dispensing regime of emergency contraception were different. Research in Australia has shown that personal attitudes and religious convictions influence the practice of dispensing emergency contraception. In the research conducted in New Mexico, 30% of pharmacists were against prescribing emergency contraception for religious or moral reasons. There were no published data in regards to pharmacists' knowledge, attitudes and dispensing practice in Serbia and such research is highly recommended.

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Section: Levonorgrestrelmentioning

confidence: 99%

Mechanism of Action, Efficacy and Safety of Emergency Hormonal Contraception (levonorgestrel and ulipristal acetate) and Attitudes of Pharmacists

Milosavljevic¹,

Ilić²,

Krajnović³

2014

Acta Facultatis Medicae Naissensis

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“…De estos 22 artículos, publicados entre 1995 y el 2010, diez estuvieron diseñados para medir el efecto sobre la ovulación (8)(9)(10)(11)(12)(13)(14)(15)(16)(17) , doce el efecto sobre el endometrio (9,12,13,(18)(19)(20)(21)(22)(23)(24)(25)(26) y tres el efecto sobre los espermatozoides (27)(28)(29) . De estos estudios, nueve correspondían a ensayos clínicos (8,9,14,15,18,19,23,24,27) , ocho a estudios cuasi-experimentales (10)(11)(12)(13)16,25,26,29) , tres a estudios observacionales (17,22,28) y dos a estudios in vitro (20,21) .…”

Section: Artículos Seleccionados Para El Análisisunclassified

“…De estos estudios, nueve correspondían a ensayos clínicos (8,9,14,15,18,19,23,24,27) , ocho a estudios cuasi-experimentales (10)(11)(12)(13)16,25,26,29) , tres a estudios observacionales (17,22,28) y dos a estudios in vitro (20,21) . Tres estudios fueron hechos en animales (los tres correspondientes a diseños cuasiexperimentales (13,16,25) ) y el resto en humanos.…”

Section: Artículos Seleccionados Para El Análisisunclassified

“…Cuando es administrado antes de la ovulación logra reducir la probabilidad de embarazos (14) . Su mecanismo de acción esta relacionado con la reducción de los niveles séricos de LH y fSH antes de la ovulación causando una ausencia de ovulación o su postergación (9)(10)(11)(12)15,17) . La efectividad en evitar la ruptura folicular también esta relacionada con el tamaño del folículo (8) .…”

Section: Efectos Sobre La Ovulaciónunclassified

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Efecto del levonorgestrel como anticonceptivo oral de emergencia en la ovulación, el endometrio y los espermatozoides

Suárez¹,

Zavala²,

Ureta³

et al. 2010

Rev Peru Med Exp Salud Publica

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RESUMENExiste amplia controversia acerca del mecanismo de acción del levonorgestrel como anticonceptivo oral de emergencia; numerosas organizaciones, tanto científicas como de la sociedad civil, muestran su disconformidad con su uso, debido a su posible acción como inductor de aborto. Con el objetivo de evaluar la evidencia científica disponible sobre los mecanismos de acción del levonorgestrel utilizado como anticonceptivo oral de emergencia (AOE), se realizó una revisión sistemática en las bases de datos Medline y Cochrane Library donde se encontró 444 artículos; después de revisar los resúmenes, se seleccionó 22 artículos, los cuales fueron evaluados a texto completo. Se encontró que el principal mecanismo de acción del levonorgestrel, a las dosis recomendadas como AOE, es la inhibición o retraso de la ovulación; no afecta a los espermatozoides en su capacidad de migración ni de penetración al óvulo. No se ha demostrado alteraciones morfológicas ni moleculares en el endometrio que puedan interferir con la implantación del huevo fecundado. No existe evidencia científica actual disponible que sustente que el uso de levonorgestrel como AOE sea abortivo.Palabras clave: Anticoncepción postcoital; Levonorgestrel; Endometrio; Ovulación; Espermatozoides (fuente: DeCS BIREME). EFFECT OF LEVONORGESTREL IN THE OVULATION, ENDOMETRIUM, AND SPERMATOZOA FOR EMERGENCY ORAL CONTRACEPTION ABSTRACTThere is wide controversy about the mechanism of action of the levonorgestrel used for emergency oral contraception, and many organizations, both scientific as well as from the civil society, show their discrepancy with its use, due to its possible action as an abortion-inducer. In order to evaluate the scientific evidence available on the mechanisms of action of the levonorgestrel used for emergency oral contraception (EOC), a systematic revision was performed in the Medline and Cochrane library databases. We found 444 articles. After reviewing the abstracts, we selected 22 articles, whose complete texts were evaluated. We found that the main mechanism of action of the levonorgestrel, given at the doses recommended for EOC, is the inhibition or retardation of the ovulation, it doesn't affect the spermatozoa in their migration or egg-penetration capacities. No morphological or molecular alterations in the endometrium that could interfere with the implantation of the fertilized egg have been demonstrated. There is no actual scientific evidence available supporting that the use of levonorgestrel for EOC is abortive.

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“…Investigations on the mechanism of action clearly revealed that LNG-EC administration during early-mid proliferative phase inhibits or delays the ovulation process whereas any endometrial morphological alterations are observed if the drug is administered during the periovulatory or early luteal phase [2,3].…”

mentioning

confidence: 99%

Endometrial progesterone receptors and levonorgestrel as emergency contraceptive

Palomino

Devoto

2009

Gynecological Endocrinology

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On the mechanisms of action of short-term levonorgestrel administration in emergency contraception

Cited by 173 publications

References 40 publications

Mechanism of Action, Efficacy and Safety of Emergency Hormonal Contraception (levonorgestrel and ulipristal acetate) and Attitudes of Pharmacists

Mechanism of Action, Efficacy and Safety of Emergency Hormonal Contraception (levonorgestrel and ulipristal acetate) and Attitudes of Pharmacists

Efecto del levonorgestrel como anticonceptivo oral de emergencia en la ovulación, el endometrio y los espermatozoides

Endometrial progesterone receptors and levonorgestrel as emergency contraceptive

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