Number of frozen treatment cycles continues to rise throughout the world
Christine Wyns, Chair of ESHRE’s EIM Consortium, delivered preliminary results of ART activity in Europe in 2018.
Published 30 June 2021
Preliminary data reported by European and global monitoring groups see success rates stable but frozen cycles continuing to rise as a proportion of total treatments; globally, 22% of all aspirations were for a freeze-all cycle.
Preliminary results from the annual European and global ART monitoring groups showed one consistent and prominent trend – that the place of freezing in all programmes continues to rise, either as part of a cumulative (fresh + frozen) or freeze-all approach. Christine Wyns, Chair of ESHRE’s EIM Consortium, reported 260,000 frozen cycles so far submitted for 2018, which already comprises more than half the total treatments recorded. Similarly, worldwide data (for 2017) reported by David Adamson on behalf of ICMART included 32% of almost 2 million monitored cycles as ‘autologous thaw’ and 56% as fresh. Even limited data for 2018 from the Chinese Society of Reproductive Medicine, presented by Dr Chengyan Deng, revealed 147,000 fresh embryos transfers against 254,000 frozen. The global trend is clearly a continuing rise in frozen treatments and decline in fresh. The ICMART data further showed that 22% of all aspirations were for a freeze-all cycle.
Both the EIM and ICMART summaries were as ever compromised by incomplete data returns, notably for EIM from the national registries of UK (some 70,000 cycles) and the Netherlands (30,000 cycles) and for ICMART from many countries of Asia and the Middle East. Nevertheless, the preliminary European data report comprised 858,159 cycles monitored from 34 countries and 1249 centres, this, said Wyns, representing around 90% of all treatments in Europe.
Globally, said Adamson, the number of cycles continues to rise, particularly in Europe and Asia. Indeed, with around 900,000 cycles monitored for 2017, Europe remains the world’s most active region according to registry returns, but, as Adamson emphasised and based on a sole report of 2020, cycles in China are estimated to be at least or beyond that total. The Chinese data report included almost 350,000 cycles, but these were only cycles reported to the Society. Otherwise, Japan, with 445,380 cycles submitted, would remain the world’s most prolific nation.
Since its first report based on European data for 1997, EIM has now recorded more than 11 million treatments cycles and 2.2 million children born. In 2018 Russia and Spain had the greatest number of cycles (155,949 and 140,498 respectively), though availability throughout Europe continues to be patchy, with Belgium, Czech Republic, Denmark, Iceland and Slovenia consistently providing greatest population access.
Outcomes from treatment in 2018 remained largely as before, with a delivery rate per aspiration/thaw of 21.5% for IVF, 19.1% for ICSI, and 23.6% for frozen/thawed transfers. Embryo donation continued to post the highest success rates, with a delivery rate per transfer of 29.3%.
Notable in both reports was the slightly higher delivery rate from conventional IVF over ICSI, despite the continuing global preference for ICSI (by a ratio of around 2:1). Some countries (many in eastern Europe) still report ICSI as their only method of fertilisation. This proportional preference has not changed since 2008.
What is also noteworthy in the data is the ever increasing number of single embryo transfers, which in North America and Europe (and indeed globally) now account for around 60% of all frozen cycles (and 50% of fresh) – although Australia/New Zealand leads the way with more than 90% of cycles. David Adamson, in noting a significant upward trend in single embryo transfers in global data, said ‘this was the way to go . . . the default approach’.
One of several caveats raised by Christine Wyns – as well as the preliminary nature of EIM data - was the effect of an increasing number of FER cycles on success rates, which has inevitably reduced the pregnancy/delivery rate per aspiration (and not per transfer). Thus, the EIM data for 2018 showed a delivery rate per transfer of 31.2% for IVF and 29.8% for ICSI, but per aspiration of 21.5% for IVF and 19.1% for ICSI. These are trends, she said, explained by the calculation itself and by the ‘technical success’ of embryo freezing.