Type of publication:
Conference abstract

Author(s):
*Nash K.; *Gittins V.; *Hatton A.; *Binnersley S.; *Hughes G.; *Kasraie J.

Citation:
Human Fertility; 2013; vol. 16 (no. 3)

Abstract:
Introduction : Following the HFEA's 'Multiple Birth, Single Embryo Transfer Policy'in 2008, blastocyst culture has become routine practice in many clinics. In our clinic, patients unable to transfer on day 5 (D5) due to failed blastocyst development or poor quality, are cultured to day 6 (D6). Supernumerary embryos not suitable for freezing on D5 are cultured to D6 and frozen if viable. We compared biochemical and clinical pregnancy rates for D5 and D6 blastocyst transfers to determine whether routine culture to D6 is beneficial. Method: Biochemical (BPR) and Clinical (CPR) pregnancy rates were compared for D5 and D6 transfers between 01/01/09 and 31/05/12. Results were analysed using Fisher's Exact test . We distinguished D6 blastocysts that were 'true'D6 from those that might have been later developing D5 blastocysts. Results: There was no significant difference in BPR (51.7%) and CPR (41.4%) for D5 (n=203) and D6 (43.5% and 30.4%, n=23) (BPR p=0.51, CPR p=0.37). One patient definitely had a 'true'D6 blastocyst. Conclusion: Culture to D6 appears beneficial as D5 and D6 pregnancy rates are similar. However, small numbers mean the D6 group results may be unreliable. One patient out of 23 had a definate D6 blastocyst making it possible that the other 22 developed late on D5. To truly distinguish D5 and 6 blastocysts we could perform transfers later on D5, but this may be impractical, particularly with blastocysts developing after 5 pm. Alternatively time-lapse technology would allow precise timing of blastulation. With these results in mind, it is likely that our policy of culturing to and freezing blastocysts on D6 regardless of the day of transfer is beneficial and will improve cumulative pregnancy rates. The number of fresh cycles a patient requires will also be reduced, ultimately benefiting the patient through reduced risk/cost, and the clinic/NHS healthcare economy.*

Type of publication:
Conference abstract

Author(s):
*Hughes G.; *Binnersley S.; *Wallbutton S.; *Gittins V.; *Parry S.; *Hatton A.; *Lavender A.; *Kasraie J.

Citation:
Human Fertility; 2013; vol. 16 (no. 3)

Abstract:
Introduction : Risks and costs associated with stimulation/egg collection mean that storage of excess viable embryos and maximisation of cumulative pregnancy rates from a single egg collection are a priority for clinics.  Should we culture all embryos not suitable for cryopreservation on day 3 (D3) and day 5 (D5) onwards to allow us to assess their viability for cryopreservation over an extended period? Materials and Methods: Retrospective  analysis of the development of 457 embryos from 89 patients that were allocated for training from D3 (n=71) and D5 (n=18) transfer patients that did not meet cryopreservation criteria on D3 (6C 15% fragmentation, 70 hours post insemination/injection) or D5 ( <= 3BB (Gardner and Schoolcraft) 118 hours post insemination). The  embryos allocated were cultured at 6% CO2 to D6 and graded each day. Results: Blastulation rates for D5 transfer patients were significantly greater than D3 transfer patients (43.04% vs 26.42%, p <= 0.0005). 1.88%  of embryos from D3 patients with 0 frozen developed to <= 3BB on D5 vs 8.57% of embryos from D3 patients with 1 frozen (p <= 0.0142). 6.29% of embryos from D3 patients with 0 frozen developed <= 3BB on D6 vs 11.43% of embryos from D3 patients with 1 frozen (p=0.1498). 11.39% of embryos from D5 transfer patients developed to <= 3BB on D6. Conclusions : This small retrospective study, in suboptimal culture conditions,  appears to show it may be beneficial to routinely culture embryos not meeting our cryopreservation criteria on D3 or D5 to D6. At present our biochemical success rates (53% vs 41%, p=0.3671) and clinical success rates for D5 vs D6 transfers (43% vs 32%, p=0.658) suggest that D6 blastocysts are as viable as D5 blastocysts. Practical
and financial implications must be taken into account but this practice may reduce 'fresh'egg collections and maximise cumulative success, thereby reducing risk and cost to the healthcare economy.

Type of publication:
Conference abstract

Author(s):
*Hatton A.; *Gittins V.; *Binnersley S.; *Hughes G.; *Lavender A.; *Kasraie J.

Citation:
Human Fertility; 2013; vol. 16 (no. 3)

Abstract:
Introduction : Blastocyst culture is now routine, but national practice is not uniform. Extended culture to day 6 (D6) may be considered controversial due to possible associated epigenetic factors and a perceived decrease in  viability of D6 blastocysts. Conversely, cryopreservation on D6 may reduce the number of fresh egg collections required, minimising risk to patients and cost to the healthcare economy, but do the benefits outweigh the  potential risks? Method : National survey of practice, protocol and outcome. Results: 40 clinics responded 7.5% did not culture to blastocyst. 92.5% cultured to blastocyst in 5-80% of treatment cycles. 59.5% cultured to D6 if  blastocysts were unavailable for transfer on day 5(D5) and between 0 and <= 90% of patients had fresh D6 transfers. Average clinical pregnancy rates (CPRs) for fresh D5 vs D6 transfers were 44.3% vs 25.7%. All clinics culturing to blastocyst cryopreserved. 89% cultured to D6 if no cryopreservation occurred on D5. 83.5% cultured remaining embryos to D6 whether or not cryopreservation occurred on D5. Average CPRs for cryopreserved D5 vs D6 blastocysts were 31% vs 28.3%. 89% believed culturing to D6 was worthwhile. Other data (e.g. culture system, cryopreservation method, carrier, media) were also collected and analysed. Conclusions : The majority of respondents cultured to, and cryopreserved, on D6. CPRs varied greatly between  centres but were generally lower in fresh D6 vs D5 transfers. Nevertheless, results suggest that D6 transfer is worthwhile for patients without D5 blastocysts. Additionally, CPRs for cryopreserved D6 blastocysts were very similar to D5 and appeared slightly higher than fresh D6. Whilst it remains to be seen whether cryopreserved D6 blastocysts are more viable than fresh, it certainly appears that cryopreservation of D6 blastocysts is effective and beneficial to both patients and the healthcare economy by reducing risks from stimulation/ egg  collections and overall costs whilst maximising cumulative success.

Type of publication:
Conference abstract

Author(s):
*Binnersley S.; *Hughes G.; *Hatton A.; *Gittins V.; *Kasraie J.

Citation:
Human Fertility; 2013; vol. 16 (no. 3)

Abstract:
Introduction : Conservation of viable embryos minimises risk to patients from repeated stimulation/egg collection, reduces costs and maximises cumulative success rates, but national practice varies greatly. Many clinics only cryopreserve top quality embryos, potentially leading to the disposal of viable embryos and unnecessary further cycles of IVF. Our clinics experience of survival rates from traditional 'slow'freezing, where fragmentation may provide additional foci for ice crystal formation, meant that, when our clinic introduced Vitrification in 2008, we continued to cryopreserve only embryos with < 5% fragmentation. However survival and pregnancy rates using vitrification were such that from May 2010, following validation of survival rates, criteria were relaxed to allow embryos with 15% fragmentation to be stored. Materials and Methods: Retrospective analysis of 156 frozen (vitrified) embryo transfer cycles. Embryos were classified as top (<=5% fragmentation) or non-top (5 to 15% fragmentation) quality. Two embryos were transferred in all cycles. Three groups were compared: 1 < Two top quality (n=109), 2=One top and one non-top (n=20), 3=two non-top (n=27) quality transferred. Vitrification cooling/warming utilised Origio media and Cryo-Bio system sealed straws. Results: There was no significant difference for patient age (p=0.48), survival rates of blastomeres in each group (97.9% vs 96.7% and 98.1%, p=0.62), biochemical pregnancy rate (36.7% vs 30.0% vs 33.3%, p=0.62), clinical pregnancy rate (20.2% vs 10.0% vs 22.2%, p=0.36), or implantation rate (12.8% vs 5% vs 12.96%, p=0.19) in all groups. Conclusion: This small retrospective study appears to show that vitrication of lower grade embryos (15% fragmentation) results in similar pregnancy rates to the vitrification of only top quality embryos. The resultant increase in the number of stored embryos and frozen embryo transfers decreases risk to the patient and cost to the healthcare economy whilst increasing the cumulative pregnancy rate from single 'fresh'IVF cycles