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15.09.2000

Newsletter No.5

Replace as many embryos as you like – one at a time. There is no negative impact of endometriosis on implantation and pregnancy rates Rescue intracytoplasmatic sperm injection (ICSI) Blastocyst score affects implantation and pregnancy outcome 1. Replace as many embryos as you like – one at a time The avoidance of multiple pregnancies in ART has increasingly become a concern over the last years, because multiple pregnancies, even twin pregnancies with the risks involved, have to be considered an adverse outcome of ART. Progress in cryopreservation with sequential transfers of one embryo potentially resulting in a high cumulative pregnancy rate on the one side and progress in embryoculture up to the blastocyst stage with a high pregnancy rate in case of the transfer of a single high quality embryo on the other side might in favourable outcomes of ART with singleton pregnancies. There is an urgent need for studies in this respect. References: Templeton A (2000) Avoiding multiple pregnancies in ART. Replace as many embryos as you like -–one at a time. Hum. Reprod. 15: 1662 Olivennes F (2000) Double trouble: yes a twin pregnancy is an adverse outcome. Hum. Reprod. 15:1663-1665 TOP 2. There is no negative impact of endometriosis on implantation and pregnancy rates The results of a study with donated oocytes to women with and without endometriosis of severe grade (III-IV) demonstrated that implantation an pregnacy rate is not affected by severe endometriosis. Any potential negative effect of severe endometriosis on the uterine environment is undetectable. Reference: Diaz I et al. (2000) Impact of stage III-IV endometriosis on recipients of sibling oocytes: matched case-control study. Fertil. Steril. 74:31-34 TOP 3. Rescue intracytoplasmatic sperm injection (ICSI) Rescue ICSI should be considered in the presence of total or near-total fertilization failure in IVF. Early application of rescue ICSI (19-20 hours after insemination) may be critical for establishing fertilization within an optimal window and producing viable embryos and pregnancies. Reference: Yuzpe AA et al. (2000) Rescue intracytoplasmatic sperm injection (ICSI) – salvaging in vitro fertilization (IVF) cycles after total or near-total fertilization failure. Fertil. Steril. 73: 1115-1119 TOP 4.Blastocyst score affects implantation and pregnancy outcome In this study all patients had transfers of two embryos that were cultured in sequential media to the blastocyst stage (day 5). When a patient received two top-scoring blastocysts (64% of patients), implantation and pregnancy rates were 70% and 87%, respectively. The twinning rate in this group was 61%. When only one top-quality blastocyst was available for transfer of the two embryos (21% of patients), the implantation and pregnancy rates were 50% and 70%. The twinning rate for this group was 50%. In contrast, when only low-scoring blastocysts were available for transfer (15% of patients), implantation and pregnancy rates were 28% and 44%, and the twinning rate was 29%. No monozygotic twins were observed in this group of patients. These data demonstrate that it might be desirable that ART should proceed towards a single blastocyst transfer. Reference: Gardner DK et al. (2000): towards a single blastocyst transfer. Fertil. Steril. 73: 1155-1158 TOP

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