Rates of single embryo transfer have steadily increased in the three regions, but especially so in Australia/New Zealand, where the twin delivry rate first fell below 5% in 2013.
Published 07 December 2020
Twenty years after its first data collection from European ART cycles, ESHRE’s IVF Monitoring Consortium has compared its cumulative findings with two other national registries – and found that Europe is the slowest on the uptake of new techniques.
ESHRE’s registry reports from European ART are monumental landmarks in the Society’s history, as relevant today as they ever have been since data were first collected in 1997. The annual reports stretch back more than 20 years, with leaders of the European IVF Monitoring Consortium (EIM) ever lamenting that as ART became more complex, so did collection of its data. Vitrification has now added a new complication and somehow outcome measures today must take account of donor egg banking and deferred transfers. ‘The complexity of present-day ART is barely reflected by current simplified data recordings,’ write the authors of a new review of data monitoring in ART, noting that all registries are ‘slow to initiate’ recordings of new techniques, and usually not without a major publication.(1) For example, freeze-all was first described in 1999 by Ferraretti and colleagues in Bologna, and but was not detailed by the CDC’s US registry until 2008, by Australia/New Zealand until 2011 and by EIM until 2017.
These three registries (CDC, ANZARD and ESHRE) are now the subject of this latest EIM review, which has compared its own cumulative data with those of the two other registries - to find comparable trends and common problems in data collection, but several discrepancies. What did the 20-year analysis find?
* As expected the numbers of recorded treatments increased considerably (though not consistently) between 1997 and 2016 (5.3-fold in Europe, 4.6-fold in the USA, and 3.0-fold in Australia and New Zealand), as did the number of centres performing them. IVF, ICSI and FET have always dominated, but egg donation is now the fourth most frequently used technique in Europe and USA (with PGT in Australia/New Zealand).
* The uptake of new treatments over time has been somewhat different in the three registries, with Europe apparently slower to adopt innovations. Even ICSI, a European development from the early 1990s and promoted exclusively by ESHRE and the Brussels group of Devroey and Van Steirteghem, was not immediately adopted as a treatment by all in European clinics. Yet ICSI overtook conventional IVF as the preferred approach from 1999 in Australia/New Zealand, from 2000 in the USA, but only from 2002 in Europe. FET cycles started to prevail over fresh in 2015 in the USA and in 2016 in Australia/New Zealand, but in Europe at that same time there were still fewer FET cycles than fresh. Similarly, a sharp rise in the number of freeze-all cycles was observed in Australia/New Zealand and the USA in 2016 (to reach 25% and 20% of all cycles, respectively), but not so in Europe, where freeze-all cycles still represented only 8.5% of the total in 2016. Is there an explanation here that European clinics (or European legislation) are more cautious about emerging trends without the support of strong evidence?
* While delivery rates have consistently risen over time in all three regions, those in the USA have been consistently higher than in Europe and Australia/New Zealand, both in fresh and FET cycles. In 2012 delivery rates from FET cycles in the USA overtook those from fresh, reaching 46% FET and 36% fresh by 2016. Outcomes from FET cycles overtook fresh in 2013 in Australia/New Zealand, and in 2016 stood at 28.4% and 23.7% respectively. However, in Europe delivery rates from fresh transfers still remained higher (25.4%) than from FET (22.7%) in 2016. The US figures, the authors explain, are seen against a background of declining started cycles since 2008 but a rising number of fresh and frozen donation cycles. Europe remains the world’s largest ART sector, with around the same number of babies born in 2016 as in USA and Australia/New Zealand combined.
* Perhaps the most important change over time has been seen in transfer policies in the adoption of single embryo transfers to reduce multiple risk, particularly in Europe, as indicated in the figure above. While studies and practice in the Nordic countries set the example, the pace in SET is now being set by Australia/New Zealand, the first continent to predominantly adopt such a policy and the first to lower the twin delivery rate below 5% in 2013.
The authors describe the aim of registries as ‘to record completely and accurately all possible treatment numbers and outcomes at different stages of the process and to come up with a coherent descriptive analysis’. However, completeness and accuracy are somewhat lacking in these reports, especially in the European figures which for 16 of the 20 years were unable to include intention-to-treat and thus underrepresent the number of started cycles (in comparison with the number of egg retrievals). For these years in Europe, performance can only be judged per retrieval and not by started cycle. A similar trend of underreporting, suggest the authors, may also be evident in complications and premature twin delivery rates. Some, such as laboratory mishaps, may simply be not reported at all.
Nevertheless, the authors describe the registry reports as a reliable barometer of ART, monitoring its progress in patient numbers, treatment modalities and accessibility. The role of ART as a driver of population policy is evident in the registries’ baby data, showing that in 2016 2.9% of all infants born in Europe were conceived by ART (the equivalent of around one child in every primary school classroom), 4.1% in Australia/New Zealand, and 1.9% in the USA. Such figures reflect the huge achievement of ART over the past 20 years, and, in the words of the authors, evidence that ‘surveillance in ART is working’. The future, they add, will be more reliant on improved software, especially with programmes able to transfer single clinic data into national and international electronic surveillance systems.
1. De Geyter C, Wyns C, Calhaz-Jorge C, et al. 20 years of the European IVF-monitoring Consortium registry: what have we learned? A comparison with registries from two other regions. Hum Reprod 2020; doi:10.1093/humrep/deaa250
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