<?xml version="1.0" encoding="ISO-8859-1"?><article xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
<front>
<journal-meta>
<journal-id>0300-9041</journal-id>
<journal-title><![CDATA[Ginecología y obstetricia de México]]></journal-title>
<abbrev-journal-title><![CDATA[Ginecol. obstet. Méx.]]></abbrev-journal-title>
<issn>0300-9041</issn>
<publisher>
<publisher-name><![CDATA[Federación Mexicana de Colegios de Obstetricia y Ginecología A.C.]]></publisher-name>
</publisher>
</journal-meta>
<article-meta>
<article-id>S0300-90412020000900575</article-id>
<article-id pub-id-type="doi">10.24245/gom.v88i9.3865</article-id>
<title-group>
<article-title xml:lang="es"><![CDATA[Desenlaces en ciclos de transferencia con embriones vitrificados: análisis de dos esquemas de preparación endometrial]]></article-title>
<article-title xml:lang="en"><![CDATA[Results in cycles of frozen-thawed embryo transfer: Analysis of two protocols of endometrial preparation]]></article-title>
</title-group>
<contrib-group>
<contrib contrib-type="author">
<name>
<surname><![CDATA[Guerrero-Vargas]]></surname>
<given-names><![CDATA[José Juan]]></given-names>
</name>
<xref ref-type="aff" rid="Aff"/>
</contrib>
<contrib contrib-type="author">
<name>
<surname><![CDATA[Barros-Delgadillo]]></surname>
<given-names><![CDATA[Juan Carlos]]></given-names>
</name>
<xref ref-type="aff" rid="Aff"/>
</contrib>
</contrib-group>
<aff id="Af1">
<institution><![CDATA[,Instituto Nacional de Perinatología Isidro Espinosa de los Reyes  ]]></institution>
<addr-line><![CDATA[Ciudad de México ]]></addr-line>
<country>México</country>
</aff>
<aff id="Af2">
<institution><![CDATA[,Instituto Nacional de Perinatología Isidro Espinosa de los Reyes Departamento de Ginecología Reproductiva ]]></institution>
<addr-line><![CDATA[Ciudad de México ]]></addr-line>
<country>México</country>
</aff>
<pub-date pub-type="pub">
<day>00</day>
<month>00</month>
<year>2020</year>
</pub-date>
<pub-date pub-type="epub">
<day>00</day>
<month>00</month>
<year>2020</year>
</pub-date>
<volume>88</volume>
<numero>9</numero>
<fpage>575</fpage>
<lpage>585</lpage>
<copyright-statement/>
<copyright-year/>
<self-uri xlink:href="http://www.scielo.org.mx/scielo.php?script=sci_arttext&amp;pid=S0300-90412020000900575&amp;lng=en&amp;nrm=iso"></self-uri><self-uri xlink:href="http://www.scielo.org.mx/scielo.php?script=sci_abstract&amp;pid=S0300-90412020000900575&amp;lng=en&amp;nrm=iso"></self-uri><self-uri xlink:href="http://www.scielo.org.mx/scielo.php?script=sci_pdf&amp;pid=S0300-90412020000900575&amp;lng=en&amp;nrm=iso"></self-uri><abstract abstract-type="short" xml:lang="es"><p><![CDATA[Resumen:  OBJETIVO: Comparar la tasa de recién nacido vivo con la de embarazo clínico-transferencia embrionaria, las características clínicas y concentraciones hormonales entre dos esquemas de preparación endometrial para transferencia de embriones desvitrificados: con un agonista de GnRH versus su sustitución con dosis altas de estrógenos.  MATERIALES Y MÉTODOS:  Estudio observacional, de cohorte histórica, efectuado en pacientes atendidas en el Instituto Nacional de Perinatología en protocolo FIV-ICSI entre enero 2017-marzo 2019. Se compararon dos esquemas de preparación endometrial: grupo A con agonista de GnRH y grupo B con estradiol a dosis de 8 mg al día sin agonista de GnRH. A todas las pacientes se les tomaron muestras de sangre para determinación de FSH, LH, estradiol y progesterona y se dio seguimiento ultrasonográfico durante la preparación endometrial.  RESULTADOS: En 99 pacientes entre 23 y 42 años, con embriones congelados, la tasa de recién nacido vivo-transferencia embrionaria fue, respectivamente, de 17.2 y 8.6% (OR 1.98; IC95%: 077-1.53) y la de embarazo clínico de 26.5 y 22.8% (OR1.09; IC95%: 0.77-1.53) en los grupos A y B, respectivamente. La duración total del ciclo, los días con estrógenos y la concentración sérica de estradiol al inicio de la progesterona alcanzaron diferencia significativa entre los grupos. No se detectaron datos clínicos ni de laboratorio sugerentes de ovulación.  CONCLUSIONES: La tasa de recién nacido vivo fue mayor con agonistas de GnRH sin alcanzar significación; sin embargo, la preparación endometrial solo con estrógenos es un esquema seguro, de menor costo y más amigable para la paciente y el médico.]]></p></abstract>
<abstract abstract-type="short" xml:lang="en"><p><![CDATA[Abstract:  OBJECTIVE: To compare the rate of live newborn with clinical pregnancy-embryo transfer, clinical characteristics and hormonal concentrations between two endometrial preparation schemes for devitrified embryo transfer: with a GnRH agonist (aGnRH) versus its replacement with high doses of estrogens.  MATERIALS AND METHODS: Historical cohort observational study conducted in patients treated at the National Institute of Perinatology under IVF-ICSI protocol between January 2017-March 2019. Two endometrial preparation schemes were compared: group A with GnRH agonist and group B with estradiol at 8 mg per day without aGnRH. All patients had blood samples taken for FSH, LH, estradiol and progesterone determination and ultrasonographic follow-up during endometrial preparation.  RESULTS: in 99 patients between 23 and 42 years of age, with frozen embryos, the live birth-embryo transfer rate was 17.2 and 8.6%, (OR 1.98; CI95%: 077-1.53) and the clinical pregnancy rate was 26.5 and 22.8% (OR1.09; CI95%: 0.77-1.53) in groups a and b, respectively. total cycle length, estrogen days and serum estradiol concentration at the beginning of progesterone reached significant difference between groups. no clinical or laboratory data suggesting ovulation were detected.  CONCLUSIONS: The rate of live newborn was higher with GnRH agonists without reaching significance; however, endometrial preparation with estrogens alone is a safe, lower cost and more patient- and physician-friendLy scheme.]]></p></abstract>
<kwd-group>
<kwd lng="es"><![CDATA[Embriones vitrificados]]></kwd>
<kwd lng="es"><![CDATA[tasa de embarazo]]></kwd>
<kwd lng="es"><![CDATA[agonistas de GnRH]]></kwd>
<kwd lng="es"><![CDATA[estradiol]]></kwd>
<kwd lng="es"><![CDATA[endometrio]]></kwd>
<kwd lng="es"><![CDATA[estrógenos]]></kwd>
<kwd lng="es"><![CDATA[transferencia de embriones]]></kwd>
<kwd lng="es"><![CDATA[recién nacido]]></kwd>
<kwd lng="en"><![CDATA[Newborn]]></kwd>
<kwd lng="en"><![CDATA[Pregnancy embryo transfer]]></kwd>
<kwd lng="en"><![CDATA[GnRH agonists]]></kwd>
<kwd lng="en"><![CDATA[Estradiol]]></kwd>
<kwd lng="en"><![CDATA[Endometrium, estrogens, embryonic structures, embryo transfer]]></kwd>
<kwd lng="en"><![CDATA[Frozen embryos]]></kwd>
<kwd lng="en"><![CDATA[Pregnancy rate]]></kwd>
</kwd-group>
</article-meta>
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