ABSTRACT
Resumen OBJETIVO: analizar las tasas de implantación y embarazo en ciclos de fertilización in vitro con transferencia electiva de un solo blastocisto, con control del factor embriónico mediante transferencia de embriones euploides. MATERIALES Y MÉTODOS: estudio retrospectivo de pacientes atendidas entre los años 2010 a 2015 en un centro privado, en protocolo de fertilización in vitro y que tuvieron, por lo menos, un embrión euploide disponible para transferencia. Para fines de estudio las pacientes se dividieron en dos grupos: 1) transferencia de embriones frescos y 2) embriones desvitrificados. Las variables categóricas se analizaron con χ2 y prueba exacta de Fisher; las variables continuas con t de Student. Se estableció significación estadística con un valor de p < 0.05. Para el análisis estadístico se usó SAS-STAT versión 9.4. RESULTADOS: se incluyeron 637 ciclos (frescos: 243 vs criopreservados: 394). La tasa de embarazo fue de 75.5% (n = 289) vs 66.3% (n = 159), embarazo clínico 62.5% (n = 235) vs 53.1% (n = 127) que fue estadísticamente significativo a favor de los ciclos criopreservados. Las tasas de embarazo múltiple fueron bajas (1.7 vs 1.6%) en ambas cohortes. CONCLUSIONES: la transferencia de un solo embrión disminuye significativamente la incidencia de embarazos múltiples y la morbilidad materna y neonatal. El mejor pronóstico en ciclos de fertilización in vitro homólogos se consigue con la transferencia de un solo embrión genéticamente equilibrado, en un ciclo posterior de preparación endometrial sintética o natural.
Abstract OBJECTIVE: To analyze the implantation and pregnancy rates in cycles of in vitro fertilization with elective transfer of a single blastocyst, with control of the embryonic factor by transfer of euploid embryos. MATERIALS AND METHODS: Retrospective analysis who included patients that underwent IVF and had at least one euploid embryo available for transfer between 2010 and 2015 on a single academic private practice. Cohorts were segregated in fresh embryo transfers (ET) vs frozen/thawed ET. Categorical variables were analyzed with χ2 and Fisher test when appropriate. Continuous variables were analyzed with Students t test. P value < 0.5 was established as statistically significant. SAS/STAT 9.4 was used for analysis. RESULTS: Six hundred and thirty-seven euploid SETs cycles (fresh cycle: n = 243; frozen/thaw cycle: n = 394) were identified. Pregnancy (75.5% (n=289) vs 66.3% (n = 159)) and clinical pregnancy rates (PR) (62.5% (n = 235) vs 53.1% (n = 127)) were statistically higher in the frozen/thaw cycles. Low rates of multiple pregnancies (1.7 and 1.6%) were observed in both cohorts. CONCLUSIONS: In one of the largest studies to date, a euploid SET during a frozen/thaw cycle showed significantly improved pregnancy and clinical PR compared to embryo transfer in fresh cycles. Single embryo transfer significantly reduces the incidence of multiple gestation and improves maternal and neonatal outcomes. An optimal outcome is achieved by the performance of a SET in FET cycles.
ABSTRACT
OBJECTIVE: Aim of this study is to evaluate the pregnancy and implantation rates in fresh-embryo transfer (ET) and frozen-thawed ET cycles in women with polycystic ovarian syndrome (PCOS). METHODS: PCOS was diagnosed by the Rotterdam criteria. In 4 cases of 72 stimulation cycles, ET was not conducted due to severe ovarian hyperstimulation syndrome (OHSS). Sixty eight cycles of fresh-ET and 40 cycles of frozen-thawed ET were included in this retrospective study. Age, gravidity, body mass index, infertility duration were compared between two groups. Number of embryos transferred, implantation rate, clinical pregnancy rate and multiple pregnancy rate were compared between two groups by using chi-square test and student's t-test. RESULTS: Number of embryos transferred showed significant difference between two groups. Fresh-ET group was 4.7 and frozen-thawed ET group was 2.8 (P<0.001). However, overall clinical outcomes with fresh-ET and frozen-thawed ET cycles were similar. Implantation rates were 8.3% vs 11.5%, clinical pregnancy rates were 27.9% vs 25.0% and multiple pregnancy rates were 36.8% vs 20.0%. CONCLUSION: Although more number of embryos were transferred in fresh-ET cycles, the clinical outcomes were similar between fresh-ET and frozen-thawed ET cycles. It may be due to decreased uterine receptivity in fresh-ET cycles. Frozen-thawed ET may be used as alternative plan for cases of severe OHSS and decreased uterine receptivity expected.