Embryo cryopreservation : the clinical outcome and couples' perspectives

Abstract

Aim: Embryo freezing is a standard practice in most fertility units. According to the latest Human Fertilisation Embryology Authority data, 2,032 babies were born in 2010 from 10,548 cycles using frozen-thawed embryos in the UK. However, the practical benefit of embryo freezing in the National Health Service (NHS) context, and the psychological impact of this practice are unknown, and need to be reviewed in the light of increasing demand for NHS support for assisted conception. Therefore, this thesis investigates the answer to the question, “Should we be freezing embryos?” from two aspects: the influence on in vitro fertilization (IVF) success rates from embryo freezing and the decision- making process by which couples decide whether or not to freeze any surplus embryos. Methods: Analysis of the cumulative pregnancy rate (CPR) following three cycles of IVF treatment including embryo freezing was performed using life table analysis. A qualitative interview study involving IVF couples was performed aiming to explore the personal and social factors that couples consider when deciding about embryo freezing. Results: It was found that embryo freezing imparts a modest benefit of about 4% increase in the overall CPR. The qualitative study showed that regardless of the practical benefits of freezing embryos and the ethical and other reservations that couples have about it, the vast majority of IVF couples wish to avail themselves of the opportunity to freeze any surplus embryos, and use every additional opportunity to maximize their chances to have a baby. The decision-making process was complex and nuanced, and was fully appreciated only on reflection. Conclusion: Findings from this study will inform couples who face the difficult decisions about embryo freezing. Although this study indicates that more detailed information may not have influenced their decision, it provides the basis for further study comparing the influence of more targeted information on freezing decisions.