What is the most relevant standard of success in assisted reproduction?: The cumulated singleton/twin delivery rates per oocyte pick-up: the CUSIDERA and CUTWIDERA.
National and international registries are essential tools for establishing new standards and comparing success rates, but they do not take into account the total pregnancy/delivery rate per oocyte recovery. In Switzerland and Germany, because of legal constraints, a maximum of three two-pronuclear zygotes are allocated for transfer whereas all the supernumerary pronuclear zygotes are immediately cryopreserved, preventing selection of the transferred embryos. We report on a 10 years' experience (1993-2002) of our centre which performs transfers of unselected embryos and cryopreservation at the two-pronuclear zygote stage. As approximately 30% of all deliveries are from cryo cycles, it is essential to take into account the contribution of the cryo transfers, and we propose therefore to evaluate, as a measure of IVF performance, the cumulated delivery rate per oocyte pick-up. This delivery rate is broken down further into the cumulated singleton delivery rate (CUSIDERA) and the cumulated twin delivery rate (CUTWIDERA). The sum (S) of these two rates is a measure of efficacy while the ratio CUTWIDERA/S as a percentage is a measure of safety of IVF treatments. Using these new indexes, the average 10 year efficacy and safety of our IVF programme were 26 and 19%, respectively. Both CUSIDERA and CUTWIDERA can be calculated easily in any clinical situation and yield useful parameters for patient counselling and internal/external benchmarking purposes.
Germond
Marc
M
Reproductive Medicine Unit, Department of Gynecology and Obstetrics, CHUV, 1011 Lausanne, Switzerland. marc.germond@chuv.hospvd.ch
Urner
Françoise
F
Chanson
Alain
A
Primi
Marie-Pierre
MP
Wirthner
Daniel
D
Senn
Alfred
A
D015925:Cryopreservation / Q000379:methods; D036861:Delivery, Obstetric / Q000706:statistics & numerical data*; D004624:Embryo Transfer; D005260:Female; D005307:Fertilization in Vitro / Q000706:statistics & numerical data; D006801:Humans; D009865:Oocytes / Q000502:physiology; D011247:Pregnancy; D027724:Reproductive Techniques, Assisted / Q000592:standards* / Q000706:statistics & numerical data; D016896:Treatment Outcome; D014427:Twins