So ESHRE comes round again, now in its 33rd year and still with the reliable regularity of a cuckoo clock. Back at the first edition, 500 pioneers registered; now, attendance seems to have settled at around 9000, including 2000 on Sunday for precongress courses. What will they all take home from Geneva, besides their bar of Toblerone and army knife?
- More on IUI, especially in the treatment of unexplained infertility. A large RCT from the Netherlands (n = 369) has found that stimulation with clomiphene citrate is just as effective as FSH in terms of live birth, ongoing pregnancy and time-to-pregnancy (Session 3, Monday 10.00 am). The study would suggest that this ‘least expensive and least invasive agent’ is now the drug of choice in IUI. Next up in the same session will be another RCT – this from New Zealand – which compared three cycles of IUI (stimulated with clomiphene) with three cycles of expectant management in couples with unexplained infertility. Results showed that the IUI option was associated with a three-fold higher live birth rate than expectant management. In 2013 NICE in the UK controversially recommended that IUI should not be routinely offered for unexplained infertility, with or without ovarian stimulation. Now results from both these trials suggest that this recommendation may need a rethink.
- A shift in thinking on ovarian response to stimulation for IVF? The Danish specialist Anders Nyboe Andersen will conclude in an invited session (Session 13, Monday 14.00) that, while stimulation dose might be individualised to maximise cumulative outcome, there still remains the need to balance oocyte yield with safety. Both the ESTHER and OPTIMIST trials cited by Andersen suggested that individualised dosing (higher for predicted low responders and vice versa) had no benefits in terms of ongoing pregnancy rates and cumulative LBR.
However, a huge multicentre study (n = 14,469) to be presented by Nicholas Polyzos on Tuesday (Session 48, Tuesday 14.15) will show that cumulative LBRs steadily increase with the number of oocytes generated in an initial stimulation cycle, even reaching 70% when 25 or more oocytes were retrieved. Although no significant decrease was detected up 20 oocytes, a drop in fresh LBRs was identified thereafter. The landmark study of Sunkara et al based on data from the HFEA database (Sunkara SK, et al. Hum Reprod 2011; 26:1768-1774) also suggested that birth rate in IVF is directly related to the number of eggs retrieved (ie, birth rates rose according to the number of eggs retrieved, but levelled out after 20 eggs). The study reported that around 15 eggs were needed to maximise the chance of delivery.
Similarly, an Australian study presented here as a poster (P-657, Venetis C, Is more better? A higher oocyte yield is independently associated with more day-3 euploid embryos) also found that a higher number of eggs retrieved in an IVF cycle is independently associated with more chromosomally normal embryos available for transfer.
So where does this leave mild IVF and the intuitive emphasis on quality, not quantity. Some studies have pointed to a negative association of a higher oocyte yield and pregnancy after fresh embryo transfer, most likely because of an adverse effect on the uterus. The study from Fauser’s group in 2007 (Heijnen EM, et al, Lancet 2007; 369: 743-749) remains a landmark and found comparable cumulative outcomes between mild and conventional IVF, and reduced patient burden.
- Cryopreserved oocytes as viable as fresh? Deborah Gook from Melbourne, one of the true pioneers of oocyte cryopreservation, will propose on Tuesday (Session 100, Tuesday 08.30) that, with evidence from large donor oocyte programmes, high survival rates can be achieved from oocyte vitrification and that the surviving oocytes can fertilise, develop and implant at rates indistinguishable from those of comparable fresh oocytes. The benefits of this are now seen not just in donor egg banks but in fertility preservation programmes too – and may well extend to other clinical contexts. Robotic automation may guarantee the standarisation of vitrification, according to embryologist Laura Rienzi (Session 28, Tuesday 09.00), whose work with Lobo et al from Spain has done much to prove the viability of vitrified oocytes.
What else from ESHRE 2017? There are new sessions from the Cochrane group and, appropriately in Geneva, the WHO. The latter’s theme is ‘unmet needs’, which must also include the provision of abstracts for the online programme book. Other high points this year – with abstracts – will include Robin Lovell-Badge on genome editing (Session 12, Monday 14.30), Jacques Cohen on mitochondrial transfer (Session 8, Monday 11.45) and Karen Sermon with the much anticipated results from the ESTEEM trial, the largest RCT to date addressing the potential benefit of aneuploidy testing by array CGH in patients of advanced maternal age (Session 39, Tuesday 12.15).
Simon Brown, Editor of Focus on Reproduction