CUMULATIVE DELIVERY RATE IN IVF CYCLES WITH OWN OOCYTES IN SPAIN: TREND OVER TIME AND ANALYSIS OF 516776 CYCLES FROM 2009 TO 2020.

Introduction

Cumulative delivery rate (CDR) has been proposed as an appropiate way of reporting success of an IVF program, incorporating both, fresh and frozen embryos. Nevertheless, views on the most appropriate parameters required to calculate such an outcome have been inconsistent.

The aim of this study was to analyze the trend of delivery rate (DR) and cumulative delivery rate (CDR) in Spain over the last 11 years in IVF/ICSI cicles with own eggs.

Methods

Data from the Spanish National Registry of Assisted Reproduction including all ovarian stimulation cycles with autologous gametes, started in Spain from 2009 to 2020 (n=680171 embryos obtained from 516776 ovarian stimulation cycles started), were analyzed. DR and CDR were studied. Oocyte donation and PGT-a cycles weren excluded. CDR was calculated as the percentage of stimulation cycles started in which, after the transfer of one or more embryos (fresh or thawed), at least one live birth is achieved.

Results

The DR per fresh transfer remains steady (aroun 24%) throughout the perior analyzed. However, DR for started cycle, which remains constant (17%) until 2013, shows a marked decline since then at a rate of 1% per year. In this same period was observed: a progressive increase in the percentage of cycles with frozen embryos (from 29% to 48%), a greater number of cryopreserved embryos (from 0.9 to 1.6 embryos per started cycle), and a continuous decrease in the number of embryos in each cryotransfer (from 2.39 to 1.42). DR after cryotransfer per started cycle has increased exponentially from 4% to 24%.

CDR showed a constant increase of 1.7% per year since 2012, going from 22% to 35% of deliveries per started cycle.

Conclusions

Although the DR per cycle has been declining, the effectiveness of cryotransfer cycles has led to a rise in the delivery cumulative rate since 2012.

Reporting CDR rather than success rates bases on fresh embryo transfer will be more appropiate to understand the treatment efficacy.