Objective To study if the number of trophectoderm (TE) biopsied cells has an impact on implantation rates. Design A retrospective cohort study in a single-center study. Setting In vitro fertilization center. Patients Patients who underwent PGT-A from January 2013 to March 2016. In total, 482 vitrified/warmed single embryo transfers were included. Interventions None. Main outcome measures Clinical pregnancies rate, implantation rate. Results Overall, clinical pregnancies per embryo transfer were higher when a regular TE were biopsied compared to larger size biopsy cells (66% (175/267) vs 53% (115/215) (p < 0.005) respectively). Pregnancy rates were also analyzed according to embryo morphology at the moment of embryo biopsy, when a good-quality embryo was transferred the clinical outcome was 75% (81/108) in group 1 and 61% (60/99) in group 2 (p < 0.05). Data was also stratified by age in patients ≤ 35 years and > 35 years. The clinical pregnancy was 67% (51/76) in women ≤ 35 years and 65% (124/191) in women > 35 years when a regular size biopsy was performed. These results significantly reduced when a larger size biopsy was performed 54% (49/91) and 53% (66/124), respectively (p < 0.05). Further investigation indicated that miscarriage rate was similar between these groups (4% (7/182) in group 1 and 5% (6/121) in group 2). Conclusions These findings underscore that when a large amount of TE cells are biopsied, it may negatively affect implantation rates, but once implanted, the embryos have the same chance to miscarry or reach term.

OBJETIVO: Determinar los resultados de la técnica de donación de ovocitos en nuestro medio. MATERIAL Y METODOS.- Entre junio de 1995y mayo de 199 7 se realizó 16 ciclos de ovodonación en transferencia embrionaria en 16 pacientes, cuyas edades fluctuaron entre 35y 48 años. Las indicaciones Para la ovodonación fueron perimenopausia y/o prueba de reserva ovárica disminuida (14 casos) y castración gonadal quirúrgica (2 casos). Se procedió a terapia de reemplazo hormonal en las pacientes receptoras y a estimulación ovárica por protocolo largo en las donantes. RESULTADOS. 71 oocitos fueron inseminados, produciendo un total de 60 pre-embriones formados, obteniendo una tasa de fertilización de 84,2%. En promedio se inseminó 4,4 ovocitos por ciclo y 3,5 pre-embriones fueron transferidos por ciclo. Se produjo 6 embarazos clínicos, con una tasa de embarazo de 3 7,5%. CONCLUSIONES: El programa de ovodonación empleada por primera vez en nuestro País, obtiene las mayores tasas de embarazo.

An egg-sharing programme provides a good opportunity for recipients and donors to achieve motherhood. At present, there are no evidences to ensure that the cryopreservation of shared eggs is not detrimental to recipients' treatment outcomes. The objective of this study was to investigate the influence of cryopreservation on donated eggs in terms of laboratorial and clinical outcomes of intracytoplasmic sperm injection (ICSI) cycles.DESIGN: Historical cohort study. MATERIALS AND METHODS: Data analyzed in this study were obtained via chart review of 267 oocyte donor ICSI cycles (age range 19-34 years), and 320 oocyte recipients (age range 26-48) undergoing 307 vitrified and 119 fresh oocyte recipient ICSI cycles, participating in an egg-sharing donation program, from 2015 to 2018, in a private university-affiliated IVF center. The sample size calculation suggested that 199 cycles would be enough to demonstrate a 20% effect with 80% power and 5% significance level considering as primary outcome blastocyst development rate. The impact of oocyte cryopreservation on recipients' ICSI outcomes was investigated using General Mixed Models fit by restricted maximum likelihood, followed by Bonferroni post hoc test for the comparison of means between fresh and warm oocyte donation groups. The model was generated using covariates as fixed effects and egg-donors and egg-recipients as random effects, with unstructured covariance structure, adjusted for oocyte dysmorphisms and other potential confounders.RESULTS: The fertilization rate (80.7% vs. 75.8%, p: 0.034), high quality embryos rate on days 2 (70.3% vs. 57.8%, p: 0.047) and 3 (50.2% vs. 34.6%, p: 0.003), normal cleavage speed rate on days 2 (90.6% vs. 77.2%, p: 0.027) and 3 (83.6% vs. 61.6%, p: 0.001), and blastocyst development rate (47.1% vs. 19.8%, p<0.001) were significantly higher on fresh oocyte donation cycles compared to warmed oocyte donation cycles. There were no statistically significant differences between fresh and warmed oocyte donation cycles in terms of high-quality blastocyst rate (71.2% vs. 62.0%, p: 0.328), implantation rate (35.7% vs. 25.7%, p: 0.182), clinical pregnancy rate (54.1% vs. 42.9%, p: 0.313), and miscarriage rate (12% vs. 15.9%, p: 0.745). The surplus embryos cryopreservation rate was significantly higher on fresh cycles compared to warmed cycles (65.4% vs. 24.1%, 0.015).CONCLUSIONS: In an egg-sharing donation program, fertilization and embryo developmental competence are reduced when vitrified oocytes are used for ICSI compared to fresh oocytes. Despite no statistical significant differences were observed in terms of pregnancy outcomes, cycles using fresh oocytes had higher rates of surplus embryo cryopreservation, which is interesting for those patients with a negative pregnancy outcome, allowing them to resort to warmed embryo transfer instead of a new cycle of oocyte donation. Efforts must be made so donor-recipient matching makes it possible to receive fresh eggs.References: NA. SUPPORT: None.

Study question Do patients with inherited thrombophilia associated to RIF and RPL benefit from anticoagulant therapy? Summary answer Low molecular weight heparin (LMWH) in patients with medium and high risk of hereditary thrombophilia, associated with RIF could improve the reproductive prognosis. What is known already Thrombophilia is a condition that can be acquired and/or inherited genetically, that is characterized by the predisposition of patients to form venous and arterial thromboembolic events. Inherited thrombophilia has been associated with different complications during pregnancy, such as RPL. Genetic variants linked to hereditary thrombophilia can be classified by the thromboembolic risk: low (F12, F13A1, FGB), medium (MTHFR, PROCR, PROS1, SERPINC1, SERPINC1 PAI–1) and high (F2, F5, GP1BA), according to Martinez - Zamora. RPL rate may reduce with anticoagulant therapy. However, there is no conclusive evidence that prophylactic treatment improves the pregnancy rate in infertile women during IVF. Study design, size, duration We performed a prospective observational study which included patients referred to Ceras Clinic between March 2018 and March 2020, due to RPL (n = 38) and RIF (n = 40). All patients underwent genetic analysis for hereditary thrombophilia(F13, F2, F5, FGB, GP1BA, MTHFR C677T, MTHFR A1298C, PAI1,, PROCR, SERPIN1 CM910058, SERPIN 1 CM920113 ,F12, PROS1) by Sanger sequencing. The characteristics of anticoagulant therapy with clinical pregnancy rate and LBR were analyzed, using chi-squared test with STATA version 16. Participants/materials, setting, methods Patients have been included in the study according to their past medical history (stroke or myocardial infarction, personal or familiar history of deep vein thrombosis or pulmonary embolism, smoking, hormone replacement therapy), and reproductive history. Two groups were formed, the first group (n = 40) corresponds to RIF, and the second (n = 38), RPL. Genetic study of hereditary thrombophilia (11 genes) was performed to examine the genetic risk and assess the administration of anticoagulant therapy. Main results and the role of chance The prevalence of pathological antecedents in patients with RIF and RPL was not statistically significant (p &gt; 0,05), indicating that the factors that contribute to poor reproductive outcomes in these two groups of patients could be similar. Patients with RIF had a medium risk of thrombophilia in 65%, followed by low risk in 32.5% and high risk in 2.5%. RPL group presented 78.95%, 15.79% and 5.26%, respectively. All patients with medium and high risk for trombophilia received anticoagulation. Clinical pregnancy rate (69.7%) and live birth rate (63.64%) were not statistically significant (p &gt; 0.05) in RPL with anticoagulant therapy, compared to RPL group who did not received treatment (clinical pregnancy rate and live birth rate in 60%). Therefore, it is proposed that there may be other factors associated with abortions that require investigation. However, clinical pregnancy rate (77.14%) and live birth rate (74.29%) were statistically significant (p &lt; 0.05) in RIF with anticoagulant therapy, compared to RIF group that did not received treatment (clinical pregnancy rate and live birth rate in 20%). This suggests that there could be a beneficial factor due to anticoagulation. Further studies are needed to assess that anticoagulant treatment could improve obstetric outcomes in patients with RIF and RPL. Limitations, reasons for caution The small number of patients assessed is the main limitation of this work. Larger studies must be designed to accurately determine participation of each mutation associated with recurrent implantation failure and recurrent pregnancy loss. The role of anticoagulant therapy should be evaluated in randomized clinical trials. Wider implications of the findings: Establishing a stronger evidence base implies that future studies should include large population groups. It is primordial to assess whether it is cost-effective to determine the risk of inherited thrombophilia in RIL and RPL, to increase the live birth rate by anticoagulant therapy. The information is controversial to this day. Trial registration number ‘not applicable’