Among the highlights of the Human Fertilisation and Embryology Authority's (HFEA) latest report on trends in fertility treatment is a continuing upturn in the number of egg donation cycles performed in the UK. In the past 20 years the use of donor eggs with donor sperm has increased 50-fold – from 27 cycles in 1991 to 1375 cycles in 2019 – while donor eggs with partner sperm increased 22-fold – to 3058 cycles in 2019. Altogether, in 2019, 4433 egg donation cycles were completed in the UK.
The HFEA attributes this increase to the wider use of egg donation in women of an older maternal age, noting a live birth rate of over 30 percent in all patients irrespective of age. Only 17 percent of patients aged 40 and over used donor eggs in 2019, but their use did nevertheless increase with age: eight percent among those aged 40-42, 21 percent for ages 43- 44 and 57 percent for ages 45-50. This trend is one we already see in the USA as reported by the United States Centres for Disease Control and Prevention, where over 12 percent (25,321 out of 196,454 cycles) of all treatment cycles are egg donation, usually in older patients.
The period covered by the report would also have found many UK women having egg donation in overseas clinics, in a pattern of cross-border care already analysed in studies from the European Society of Human Reproduction and Embryology. In addition, we had evidence as published in the journal Human Reproduction that during this period donor eggs and sperm were being sent across borders and between countries, as well as patients travelling to different countries for fertility treatment. However, in 2020 with the outbreak of the COVID-19 pandemic in March, many of these overseas clinics – in Spain, Ukraine, USA and Cyprus – would have been out of bounds to most egg donation patients from the UK, and still off limits in 2021. Based on these restrictions and observations of our own practice at the London Egg Bank, we think it can be stated with some confidence that the UK's primary source of donor eggs is no longer overseas clinics. Egg donation has come home.
Even factoring in the restrictions of the pandemic, this represents a seismic shift and one we forecasted in 2020 in the journal Reproductive Biomedicine Online. We wrote that using frozen eggs 'will quickly become the default standard practice in egg donation' in contrast to the previous use of 'fresh eggs' taken from women participating in IVF egg collections as egg sharers or donors related to patients. We further added that there will be no need for overseas travel, no need to wait for a suitable donor to become available at overseas clinics or for synchronised cycles. A greater choice of donors, and a more efficient programme at a lower cost will be available within the UK. The basis of this forecast was the development of vitrification technology and the ability it has conferred to frozen eggs to retain the same viability as fresh once warmed.
Our more recent publication in the journal Reproductive Biomedicine Online of an analysis of almost 500 egg freezing cycles and subsequent transfers in 705 recipients in a group of patients at the London Egg Bank demonstrates the extent to which vitrification is revolutionising egg donation in the UK and how domestic sourcing of donor eggs can now meet the demands and expectations of recipient patients.
The large group of altruistic donors in this study represents wholly UK sourced donor eggs recruited between January 2017 and December 2019 in a programme introduced to prospective donors and recipients via seminars, the London Egg Bank website and social media. The overall live birth rate per transfer among the 559 recipients matched to donors was 37.9 percent, which varied according to identified predictive factors in the donors (age and ovarian reserve). Estimates of cumulative live birth rates after three embryo transfers exceeded 60 percent. However, recipient age was not a significant predictor of outcome. Singletons were born in 95.5 percent of gestations.
This study not only demonstrates the excellent viability of frozen donor eggs in this series, but also reaffirms the potential to provide enough donor eggs to meet demand in the UK derived only from domestic altruistic donors and recipients turning to a local clinic for treatment. Concurring with the trend for older women to use donor eggs seen in the HFEA report, recipients in this study had a median age of 44 years, with age and low ovarian reserve the most common reasons for seeking treatment. Two-thirds of them had frozen embryos left in storage after treatment.
These results compare well with other studies, although one study from Spain in a large group of egg donation patients sought to compare outcomes from frozen and fresh donor eggs, while another from the USA involved predominantly the transfer of multiple embryos. Our study, over a period of three years, involved a consecutive group of treatments that involved only frozen-thawed eggs, and with a single embryo transfer rate of 87 percent.
While some predictive factors (mainly relating to the donor) do have an influence on outcome, the results of this study should be reassuring to patients that a UK-based domestic egg donation programme can achieve excellent results comparable with those of other cryobanks across the world. The restrictions of the COVID-19 pandemic may well have frustrated most cross-border initiatives in the past year or so, but frozen egg banking can flourish here in the UK, and is now in a prime position to meet the patient demands implicit in the HFEA's latest review.