Post-coital administration of levonorgestrel does not interfere with post-fertilization events in the new-world monkey Cebus apella

Ortiz, Mauricio; Ortíz, Rita; Fuentes, Macarena; Parraguez, Vı́ctor H.; Croxatto, Horacio B.

doi:10.1093/humrep/deh180

Cited by 77 publications

(52 citation statements)

References 5 publications

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“…Given the importance of safe sex practices to reduce the spread of STDs and HIV, our results should serve as a further call to local religious leaders who still attempt to block the use of condoms and other modern contraceptive methods. Even more untenable are their false arguments, like claiming that condoms fail to protect against HIV or that the emergency contraceptive pill induces abortion 18 , ignoring current scientific evidence to the contrary 19,20,21,22 . The impact of their erroneous claims in condoning unsafe sexual behavior by their more devote followers, as observed in this study, can have tragic consequences that are totally unacceptable in a country like Brazil with a secular political system.…”

Section: Discussionmentioning

confidence: 99%

Factors associated with safe sex among public school students in Minas Gerais, Brazil

et al. 2007

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Section: Discussionmentioning

confidence: 99%

Factors associated with safe sex among public school students in Minas Gerais, Brazil

et al. 2007

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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

“…La efectividad en evitar la ruptura folicular también esta relacionada con el tamaño del folículo (8) . Los estudios realizados en animales también muestran que el LNG administrado tempranamente en el período preovulatorio es efectivo en suprimir o atrasar la ovulación (13,16) . La efectividad parece ser dependiente solo del momento de aplicación con respecto a la ovulación.…”

Section: Efectos Sobre La Ovulaciónunclassified

“…La efectividad parece ser dependiente solo del momento de aplicación con respecto a la ovulación. Al igual que en humanos, se observa que si se administra muy cerca de la ovulación, la tasa de embarazo es igual que en el grupo control (16) .…”

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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Progesterone, but not luteal estrogen, is required for the establishment of pregnancy in the new world monkey Cebus apella

Ortiz¹,

Ortíz²,

Garfield³

et al. 2007

American J Primatol

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The aim of this study was to examine the requirement of luteal progesterone or luteal estrogen for the establishment of pregnancy in the Cebus monkey and to test in a primate species the synergism between RU 486 and letrozole (LTZ) found in rodents for inhibiting implantation. Exposure of target tissues to either hormone was suppressed during the mid-luteal phase of mating cycles by subcutaneous administration of the antiprogestin (RU 486), the aromatase inhibitor LTZ or the antiestrogen (ICI 182780) on days 4-7 of the luteal phase. Administration of 0.1 or 0.5 mg/kg of LTZ on days 5-7 of the luteal phase caused a profound drop in the levels of E(2) in all animals, whereas administration of ICI 182780 0.2 mg/kg on days 4-6 of the luteal phase had the opposite effect. The pregnancy rate in vehicle treated cycles of the same females was (58.3%). Treatment with RU 486, 0.8 mg/kg/day on days 5-7 of the luteal phase-induced endometrial bleeding in 3/5 mated females none of which became pregnant, whereas pregnancy was confirmed in one of the two animals that did not bled. Treatment with RU 486, 0.4 mg/kg/day alone or with LTZ on days 5-7 or ICI 182780 alone, on days 4-6 of the luteal phase failed to induce bleeding, allowing the establishment of pregnancy in 50.0-66.6% of the animals in these groups. We conclude that in Cebus monkeys, progesterone but not luteal estradiol is required for the establishment of pregnancy and that RU 486 and LTZ do not exhibit in this species the synergism found in rodents.

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Post-coital administration of levonorgestrel does not interfere with post-fertilization events in the new-world monkey Cebus apella

Cited by 77 publications

References 5 publications

Factors associated with safe sex among public school students in Minas Gerais, Brazil

Factors associated with safe sex among public school students in Minas Gerais, Brazil

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

Progesterone, but not luteal estrogen, is required for the establishment of pregnancy in the new world monkey Cebus apella

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