Evolución y resultados de la transferencia de un embrión en un programa de donación de ovocitos

Abstract

IntroductionMultiple pregnancy involves a high risk of obstetric and perinatal complications. The only way to prevent multiple gestation in ART is to transfer one embryo. The primary objective of this study is to assess the evolution in the proportion of single embryo transfers and the multiple pregnancy rate in our Oocyte Donation programme. As a secondary objective the efficacy of selective single embryo transfer (SET) is verified, following the application of embryo number- and quality-related criteria for the purpose of recommendation. Material and methodsRetrospective analysis of the results between 2004 and 2014 and prospective analysis of cumulative pregnancy, live birth and multiple pregnancy rates between December 2012 and October 2014, following SET in patients with ≥5 cleaved embryos, ≥2 of which are good-quality embryos. ResultsSingle embryo transfer increased from 2.6% (2004) to 43.1% (2014), with a decrease in the twin pregnancy rate from 32.5% (2004) to 22.5% (2014). The application of embryo criteria led to the recommendation of SET in 48.13% of the cycles (500/1038) of which 59.4% were performed (297/500). Pregnancy and live birth rates were significantly lower in the SET group than in the DET (double embryo transfer) group. However, cumulative (fresh+frozen and thawed transfer) pregnancy and live birth rates were similar (SET: 73.1% and 55.9 vs DET: 70% and 50.2%; P>.05, respectively), with a higher cumulative multiple pregnancy rate in DET (SET: 8.8% vs DET: 34.5%; P<.05). DiscussionThe progressive increase in the proportion of single embryo transfer becomes more noticeable when the SET criteria are followed, leading to a considerable, albeit still insufficient, decline in the multiple gestation rate. The cumulative results obtained contribute to the gradual degree of acceptance and safety of single embryo transfer and endorse its performance in good-prognosis patients.