Definition of a clinical strategy to enhance the efficacy, efficiency and safety of egg donation cycles with imported vitrified oocytes.

Which is the most suitable clinical strategy in egg donation IVF cycles conducted with imported donated vitrified oocytes? The importation, and allocation, of at least eight vitrified eggs per couple during an egg donation cycle is associated with a high cumulative live birth delivery rate per cycle, as well as the confident adoption of a single blastocyst transfer strategy to minimize the risk of multiple pregnancies. IVF using donor eggs is commonly used worldwide to treat women who are unable to conceive with their own oocytes. In 2014, the Constitutional Court (n.162/2014) gave permission for gamete donation to be allowed for ART in Italy. Initially recommended as a therapeutic approach for premature ovarian insufficiency, the use of donated oocytes has become more and more common. In countries such as Italy, fresh oocyte donation is theoretically possible, but practically impossible due to the lack of donors. In fact, the Italian law does not allow reimbursement to the young women, who can only voluntarily donate their eggs. Therefore, Italian IVF centers have established several collaborations with international oocyte cryo-banks. The most popular workflow involves the importation of donated oocytes that have been vitrified. However, recent evidence has questioned the overall efficacy of such an approach. This is because detrimental effects arising from oocyte vitrification and warming might reduce the number of eggs available for insemination, with a consequential reduction in the achievable live birth rate per cycle. This was a longitudinal cohort study, conducted between October 2015 and December 2018 at two private IVF centers. Overall, 273 couples were treated (mean maternal age: 42.5 ± 3.5 years, range: 31-50 years; mean donor age: 25.7 ± 4.2, 20-35 years) with oocytes purchased from three different Spanish egg banks. We performed an overall analysis, as well as several sub-analyses clustering the data according to the year of treatment (2015-2016, 2017 or 2018), the number of warmed (6, 7, 8 or 9) and surviving oocytes (≤4, 5, 6, 7, 8 or 9) and the cycle strategy adopted (cleavage stage embryo transfer and vitrification, cleavage stage embryo transfer and blastocyst vitrification, blastocyst stage embryo transfer and vitrification). This study aimed to create a workflow to maximize IVF efficacy, efficiency, and safety, during egg donation cycles with imported vitrified oocytes. The primary outcome was the cumulative live birth delivery rate among completed cycles (i.e. cycles where at least a delivery of a live birth was achieved, or no embryo was produced/left to transfer). All cycles, along with their embryological, obstetric and neonatal outcomes, were registered and inspected. The survival rate after warming was 86 ± 16%. When 6, 7, 8 and 9 oocytes were warmed, 94, 100, 72 and 70% of cycles were completed, resulting in 35, 44, 69 and 59% cumulative live birth delivery rates per completed cycle, respectively. When ≤4, 5, 6, 7, 8 and 9 oocytes survived, 98, 94, 85, 84, 66 and 68% of cycles were completed, resulting in 16, 46, 50, 61, 76 and 60% cumulative live birth delivery rates per completed cycle, respectively. When correcting for donor age, and oocyte bank, in a multivariate logistic regression analysis, warming eight to nine oocytes resulted in an odds ratio (OR) of 2.5 (95% CI: 1.07-6.03, P = 0.03) for the cumulative live birth delivery rate per completed cycle with respect to six to seven oocytes. Similarly, when seven to nine oocytes survived warming, the OR was 2.7 (95% CI: 1.28-5.71, P < 0.01) with respect to ≤6 oocytes. When cleavage stage embryos were transferred, a single embryo transfer strategy was adopted in 17% of cases (N = 28/162); the live birth delivery rate per transfer was 26% (n = 43/162), but among the pregnancies to term, 28% involved twins (n = 12/43). Conversely, when blastocysts were transferred, a single embryo transfer strategy was adopted in 96% of cases (n = 224/234) with a 30% live birth delivery rate per transfer (N = 70/234), and the pregnancies to term were all singleton (n = 70/70). During the study period, 125 babies were born from 113 patients. When comparing the obstetric outcomes for the cleavage and blastocyst stage transfer strategies, the only significant difference was the prevalence of low birthweight: 34 versus 5%, respectively (P < 0.01). However, several significant differences were identified when comparing singleton with twin pregnancies; in fact, the latter resulted in a generally lower birthweight (mean ± SD: 3048 ± 566 g versus 2271 ± 247 g, P < 0.01), a significantly shorter gestation (38 ± 2 versus 36 ± 2 weeks, P < 0.01), solely Caesarean sections (72 versus 100%, P = 0.02), a higher prevalence of low birthweight (8 versus 86%, P < 0.01), small newborns for gestational age (24 versus 57%, P = 0.02) and preterm births (25 versus 86%, P < 0.01). This retrospective study should now be confirmed across several IVF centers and with a greater sample size in order to improve the accuracy of the sub-analyses. Single blastocyst transfer is the most suitable approach to achieve high success rates per procedure, thereby also limiting the obstetric complications that arise from twin pregnancies in oocyte donation programs. In this regard, the larger the cohort of imported donated vitrified oocytes, the more efficient the management of each cycle. None. None.

Rienzi L ，Cimadomo D ，Maggiulli R ，Vaiarelli A ，Dusi L ，Buffo L ，Amendola MG ，Colamaria S ，Giuliani M ，Bruno G ，Stoppa M ，Ubaldi FM ... -  《-》

Efficiency and efficacy of vitrification in 35 654 sibling oocytes from donation cycles.

Is oocyte vitrification/warming as efficient and effective as using fresh oocytes in donation cycles? IVF with vitrified donor oocytes is less efficient than using fresh oocytes, but its efficacy remains comparable to that of fresh cycles. Oocyte vitrification is used to preserve the reproductive potential of oocytes. A small number of randomized controlled trials carried out by experienced groups have shown that this technique provides fertilization, pregnancy, implantation and ongoing pregnancy rates comparable to those of fresh oocytes. However, large registry-based analyses have consistently reported lower live birth rates (LBRs) in cycles using vitrified oocytes. It is not clear whether this decrease may be due to the effect of vitrification per se on the oocytes or to the lower efficiency of the technique, as some of the oocytes do not survive after warming. Retrospective cohort analysis of 1844 cycles of oocyte donation (37 520 oocytes), each donor in the study provided enough oocytes for at least one reception cycle with fresh oocytes (2561 cycles) and one reception cycle with vitrified oocytes (2471 cycles) from the same ovarian stimulation (sibling oocytes). Overall, 35 654 oocytes were considered in the analysis. All embryo transfers (n = 5032) were carried out between 2011 and 2017. Differences in reproductive outcomes after the first embryo transfer were evaluated using Pearson's Chi-squared test and regression analysis adjusted for recipient's age, BMI, sperm origin and state, day of embryo transfer, morphological score and number of transferred embryos. We performed two additional sub-analyses, to test whether the efficiency and/or effectiveness of vitrification/warming impacts reproductive results. One analysis included paired cycles where the same number of fresh and vitrified oocytes were available for ICSI (SAME sub-analysis), while the second analysis included those cycles with a 100% survival rate post-warming (SAME100 sub-analysis). Baseline and cycle characteristics of participants were comparable between groups. Overall, fertilization rates and embryo morphological scores were significantly lower (P < 0.001) when using vitrified oocytes; moreover, vitrified oocytes also resulted in lower reproductive outcomes than sibling fresh oocytes using both unadjusted and adjusted analyses: ongoing pregnancy (32.1% versus 37.5%; P < 0.001; OR 0.88, 95% CI 0.77, 1.00) and live birth (32.1% versus 31.9%; P = 0.92; OR 1.16, 95% CI 0.90, 1.49). However, when the efficiency of warming was taken into account, reproductive outcomes in recipients became comparable: ongoing pregnancy (33.5% versus 34.1%; P = 0.82; OR 1.11, 95% CI 0.87, 1.43) and LBR (32.1% versus 32%; P = 0.97; OR 1.15, 95% CI 0.89, 1.48). Moreover, after selecting only cycles that, in addition to having the same number of oocytes available for ICSI, also had 100% post-warming survival rate in the vitrified group, reproductive outcomes were also comparable between fresh and vitrified oocytes: ongoing pregnancy (34.8% versus 32.4%; P = 0.42; OR 1.32, 95% CI 0.98, 1.77) and live birth (32.9% versus 31.0%; P = 0.52; OR 1.27, 95% CI 0.95, 1.71), indicating that reproductive outcomes of these cycles are affected by the efficiency of the vitrification/warming technique performed rather than the oocyte damage due to the fast cooling process to which oocytes are subjected. An open vitrification system was used for all cases, and oocyte vitrification/warming was performed by experienced embryologists with consistently high survival rates; caution must be exerted when extrapolating our results to data obtained using other open vitrification systems, closed vitrification systems or to IVF units with survival rates <90%. This is the largest cohort study comparing reproductive outcomes of vitrified and fresh sibling donor oocytes to date. We found that, when the number of oocytes available after warming is equal to the number of fresh oocytes, reproductive results including live birth are comparable. Consequently, the efficiency of vitrification must be taken into account to achieve the same reproductive outcomes as with fresh oocytes. We recommend implementing strict indicators of vitrification/warming efficiency in clinics and refining vitrification/warming protocols to maximize survival. This work was supported by intramural funding of Clínica EUGIN and by the Secretary for Universities and Research of the Ministry of Economy and Knowledge of the Government of Catalonia (GENCAT 2015 DI 048). The authors declare no conflicts of interest. N/A.

Cornet-Bartolomé D ，Rodriguez A ，García D ，Barragán M ，Vassena R ... -  《-》

Associations of blastocyst features, trophectoderm biopsy and other laboratory practice with post-warming behavior and implantation.

Cimadomo D ，Capalbo A ，Levi-Setti PE ，Soscia D ，Orlando G ，Albani E ，Parini V ，Stoppa M ，Dovere L ，Tacconi L ，Ievoli E ，Maggiulli R ，Ubaldi FM ，Rienzi L ... -  《-》

How does vitrification affect oocyte viability in oocyte donation cycles? A prospective study to compare outcomes achieved with fresh versus vitrified sibling oocytes.

Solé M ，Santaló J ，Boada M ，Clua E ，Rodríguez I ，Martínez F ，Coroleu B ，Barri PN ，Veiga A ... -  《-》

The euploid blastocysts obtained after luteal phase stimulation show the same clinical, obstetric and perinatal outcomes as follicular phase stimulation-derived ones: a multicenter study.

Are the reproductive outcomes (clinical, obstetric and perinatal) different between follicular phase stimulation (FPS)- and luteal phase stimulation (LPS)-derived euploid blastocysts? No difference was observed between FPS- and LPS-derived euploid blastocysts after vitrified-warmed single embryo transfer (SET). Technical improvements in IVF allow the implementation non-conventional controlled ovarian stimulation (COS) protocols for oncologic and poor prognosis patients. One of these protocols begins LPS 5 days after FPS is ended (DuoStim). Although, several studies have reported similar embryological outcomes (e.g. fertilization, blastulation, euploidy) between FPS- and LPS-derived cohort of oocytes, information on the reproductive (clinical, obstetric and perinatal) outcomes of LPS-derived blastocysts is limited to small and retrospective studies. Multicenter study conducted between October 2015 and March 2019 including all vitrified-warmed euploid single blastocyst transfers after DuoStim. Only first transfers of good quality blastocysts (≥BB according to Gardner and Schoolcraft's classification) were included. If euploid blastocysts obtained after both FPS and LPS were available the embryo to transfer was chosen blindly. The primary outcome was the live birth rate (LBR) per vitrified-warmed single euploid blastocyst transfer in the two groups. To achieve 80% power (α = 0.05) to rule-out a 15% difference in the LBR, a total of 366 first transfers were required. Every other clinical, as well as obstetric and perinatal outcomes, were recorded. Throughout the study period, 827 patients concluded a DuoStim cycle and among them, 339 did not identify any transferable blastocyst, 145 had an euploid blastocyst after FPS, 186 after LPS and 157 after both FPS and LPS. Fifty transfers of poor quality euploid blastocysts were excluded and 49 patients did not undergo an embryo transfer during the study period. Thus, 389 patients had a vitrified-warmed SET of a good quality euploid blastocyst (182 after FPS and 207 after LPS). For 126 cases (32%) where both FPS- and LPS-derived good quality blastocysts were available, the embryo transferred was chosen blindly with a 'True Random Number Generator' function where '0' stood for FPS-derived euploid blastocysts and '1' for LPS-derived ones (n = 70 and 56, respectively) on the website random.org. All embryos were obtained with the same ovarian stimulation protocol in FPS and LPS (GnRH antagonist protocol with fixed dose of rec-FSH plus rec-LH and GnRH-agonist trigger), culture conditions (continuous culture in a humidified atmosphere with 37°C, 6% CO2 and 5% O2) and laboratory protocols (ICSI, trophectoderm biopsy in Day 5-7 without assisted hatching in Day 3, vitrification and comprehensive chromosome testing). The women whose embryos were included had similar age (FPS: 38.5 ± 3.1 and LPS: 38.5 ± 3.2 years), prevalence of male factor, antral follicle count, basal hormonal characteristics, main cause of infertility and previous reproductive history (i.e. previous live births, miscarriages and implantation failures) whether the embryo came from FPS or LPS. All transfers were conducted after warming in an artificial cycle. The blastocysts transferred after FPS and LPS were similar in terms of day of full-development and morphological quality. The positive pregnancy test rates for FPS- and LPS-derived euploid blastocysts were 57% and 62%, biochemical pregnancy loss rates were 10% and 8%, miscarriage rates were 15% and 14% and LBRs were 44% (n = 80/182, 95% CI 37-51%) and 49% (n = 102/207, 95% CI 42-56%; P = 0.3), respectively. The overall odds ratio for live birth (LPS vs FPS (reference)) adjusted for day of blastocyst development and quality, was 1.3, 95% CI 0.8-2.0, P = 0.2. Among patients with euploid blastocysts obtained following both FPS and LPS, the LBRs were also similar (53% (n = 37/70, 95% CI 41-65%) and 48% (n = 27/56, 95% CI 35-62%) respectively; P = 0.7). Gestational issues were experienced by 7.5% of pregnant women after FPS- and 10% of women following LPS-derived euploid single blastocyst transfer. Perinatal issues were reported in 5% and 0% of the FPS- and LPS-derived newborns, respectively. The gestational weeks and birthweight were similar in the two groups. A 5% pre-term delivery rate was reported in both groups. A low birthweight was registered in 2.5% and 5% of the newborns, while 4% and 7% showed high birthweight, in FPS- and LPS-derived euploid blastocyst, respectively. Encompassing the 81 FPS-derived newborns, a total of 9% were small and 11% large for gestational age. Among the 102 LPS-derived newborns, 8% were small and 6% large for gestational age. No significant difference was reported for all these comparisons. The LPS-derived blastocysts were all obtained after FPS in a DuoStim protocol. Therefore, studies are required with LPS-only, late-FPS and random start approaches. The study is powered to assess differences in the LBR per embryo transfer, therefore obstetric and perinatal outcomes should be considered observational. Although prospective, the study was not registered. This study represents a further backing of the safety of non-conventional COS protocols. Therefore, LPS after FPS (DuoStim protocol) is confirmed a feasible and efficient approach also from clinical, obstetric and perinatal perspectives, targeted at patients who need to reach the transfer of an euploid blastocyst in the shortest timeframe possible due to reasons such as cancer, advanced maternal age and/or reduced ovarian reserve and poor ovarian response. None. N/A.

Vaiarelli A ，Cimadomo D ，Alviggi E ，Sansone A ，Trabucco E ，Dusi L ，Buffo L ，Barnocchi N ，Fiorini F ，Colamaria S ，Giuliani M ，Argento C ，Rienzi L ，Ubaldi FM ... -  《-》