Reconceiving egg freezing: insights from an analysis of 5 years of data from a UK clinic

Abstract

Research question: What can we learn from 5 years of egg-freezing practice in the UK? What are the different categories of egg freezing, and what are the social and demographic characteristics of patients, and their decisions regarding subsequent storage or thawing?

Design: A retrospective analysis of clinical and laboratory data of all 514 cycles of 'own' egg freezing conducted at the London Women's Clinic in the 5-year period from the start of 2012 to the end of 2016.

Results: This analysis, the first of its kind, develops a clearer picture of egg-freezing trends in the UK and fills in the details behind the Human Fertilisation and Embryology Authority's national figures. Four different categories of egg freezing are identified and the appropriate category allocated to each of the 514 cycles undertaken by 352 patients. To the established categories of 'medical' and 'social' already discussed in the literature, we add the two new categories of 'clinical' and 'incidental' egg freezing. We show how each of these categories presents a distinct egg-freezing patient profile, and discuss the similarities and differences between them across variables such as age, relationship status, number of eggs frozen, number of egg-freezing cycles undertaken, and the current status of frozen eggs.

Conclusions: The data require a reconceptualization of the phenomenon of egg freezing, and argue for the importance of clearly and accurately differentiating between different categories of egg-freezing practice in clinical and national data collection in order to adequately inform future practice, regulation and the decision-making processes of patients considering these procedures.

Keywords: Egg freezing; Ethics; Fertility preservation; Oocyte cryopreservation; Regulation; Sociology of assisted reproduction.