by Mary M. Fusillo, RN, BSN, MS

I spent the first week of July enjoying the chilly weather in Helsinki, Finland while attending the annual ESHRE (European Society for Human Reproduction and Embryology) conference. Over 8,000 of my fellow women’s health and fertility experts joined together in Helsinki to learn the newest information to improve outcomes for our patients.

I am always on the lookout for scientific evidence and clinical trials as it relates to oocyte donation and third party parenting. The Spanish IVF clinic and their Santiago, Chile satellite clinic, IVI, is noted for their rigorous use of clinical trials to drive innovation and this year’s ESHRE was no exception. One of the abstracts caught my attention with its discussion of the economic model of egg vitrification (egg freezing) versus fresh egg cycles.

Titled, Predictive model to determine the optimal number of fresh versus vitrified oocytes to obtain similar implantation and live birth rates in a donor oocyte program.¹ this abstract developed a model to determine the optimal number of oocytes needed to achieve a pregnancy/live birth. Their sample size was 645 donor cycles with 462 fresh and 183 vitrified with a total of 9583 oocytes.

They used seven parameters to build their predictive model including, Donor and Recipient BMI, sperm concentration, E2 at trigger, gamete origin (fresh vs. frozen) and previous pregnancy outcomes for the donor (had a previous donation resulted in a live birth).

From this data they were able to predict outcomes with a 70% reliability rate. Stating in the abstract, “According to our data, more vitrified oocytes are needed to achieve similar rates of implantation and live birth compared to fresh oocytes.” Since the vast majority of IVF programs using vitrified/frozen eggs, the numbers needed for successful birth increase over the use of fresh eggs.

With this type of algorithm and research the cost benefit ratio of frozen versus fresh cycles can be rapidly calculated. In the US, most egg freezing programs utilize a model of purchasing a set of frozen eggs from a clinic or egg bank which usually numbers 6 – 8 eggs. This model shows that may not be enough to achieve the desired outcome.

Much research is pending on the outcomes of fresh versus frozen but this tool developed by IVI may be what patients need to be able to access to determine the desirability of frozen oocytes over fresh cycles.

Notes:

1. Predictive model to determine the optimal number of fresh versus vitrified oocytes to obtain similar implantation and live birth rates in a donor oocyte program. M. Calonge¹, D. Morbeck², F. Gonzalez-Valdez³, J. Remohi⁴, A. Pellicer⁴, M. Meseguer⁵, C. Troncoso⁶.
   (1) IVI Santiago de Chile, IVF Laboratory, Santiago-RM, Chile. (2) Mayo Clinic, IVF Laboratory, Rochester, U.S.A.. (3) Pontificia Universidad Catolica de Chile, Engineering, Santiago, Chile. (4) IVI Valencia, Gynecology, Valencia, Spain. (5) IVI Valencia, IVF Laboratory, Valencia, Spain. (6) IVI Santiago de Chile, Gynecology, Santiago-RM, Chile