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BARCELONA: PGD CONSORTIUM

Back on track with annual data reports

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Data collection now based on analyses, not on cycles. Breast cancer now prevalent in monogenic testing.

Data collection by the ESHRE PGD Consortium has undergone a complete revision in the past few years. Gone is the manual recording of the past, now replaced by a more efficient online platform for prospective data collection. However, labour-intensity remains, with detailed information still required, as well as the collaboration of genetics and IVF.

The Consortium's Chair, Martine de Rycke, explained in Barcelona that all data collection from 1997 (when the Consortium was founded) to 2012 was based on cycles; from last year, however, with the introduction of the new online system, data collection is now based on the analysis.

So far, said Martine, 118 centres are members of the Consortium. She added too that the Consortium had adopted the new terminology defined by ICMART and associates (including ESHRE) and was thus now defining PGD and PGS as PGT (testing), with extensions for aneuploidy testing (PGT-A), monogenic defects (PGT-M) and chromosomal structural rearrangements (PGT-SR). No mention was made of whether the PGD Consortium would become the PGT Consortium.

The data presented in Barcelona were for 2016, with follow-up to January 2018. This picks up the former single-year pattern of data collection following a hiatus in which the traditional annual reports were replaced by summary data (for 2013-15).

"We used to report on cycles from one complete year with follow-up of nine months in the following year," Martine explained, "but this has now changed to analyses of one year with follow-up of 12 months." The PGD Consortium's has since agreed that the data will again be assessed after a 36 months follow-up to report on cumulative outcomes.

The preliminary data for 2016 was based on 4605 analyses submitted by 58 centres. Most indications were either for PGT-A (41%) and PGT-M (40%), with - for the first time - initial blastocyst biopsy (day 5 and day 6) favoured over cleavage stage.

How was the testing done? Most PGT-M cases, as before, were analysed with PCR, though the nature of those cases has changed over the past decade, with testing for the two BRCA breast cancer genes now very prevalent. Clinical pregnancy rates remained fairly steady at around 30%, with a slight decline in 2016 possibly explained by a greater use of freezing.

Martine reported further progress from the Consortium working groups, with 2010 guidelines set for update in the organisation of a PGT centre, embryo biopsy, testing for chromosomal structural and numerical aberrations, and testing for single gene defects (PGT-M).