BACKGROUND Latest advancement of minimum volume vitrification methods has resulted in a dramatic increase in the efficiency of the process. 11 second oocyte warming cycles were then performed in non-pregnant patients of the same cohort. The overall ongoing pregnancy rates obtained in the fresh, and first and second warming cycles were 37.4, 25.0 and 27.3%, respectively. The overall cumulative ongoing clinical pregnancy rate observed per stimulation cycle was 53.3%. Maternal age was the only characteristic found to influence the reproductive outcome, with an inverse correlation between the age >40 and the ongoing pregnancy rates (= 0.04, by Cox regression analysis). CONCLUSIONS High cumulative ongoing pregnancy rates can be obtained Exherin IC50 with transfers of embryos derived from fresh and cryopreserved oocytes in a typical infertile population. Female age significantly affects outcomes in this system. and developmental potential. According to a multicenter study, pregnancies and perinatal outcomes do not appear to be altered by oocyte vitrification (Chian embryo culture. In warmed oocyte cycles, embryos were transferred in the course GLP-1 (7-37) Acetate of a natural cycle. The luteal phase was supported by vaginal micronized progesterone. Oocyte vitrification and warming procedures The vitrification and warming procedure has been described earlier (Rienzi = 0.05). Regarding the different age groups, ongoing pregnancy rates of: 40.3% (29/72), 45.7% (16/35) and 0% (0/2) were observed in women aged <34 years (NS); 41.7% (20/48), 11.1% (3/27) and 33.3% (1/3) in women aged 35C37 years (= 0.02); 36.6% (15/41), 20.0% (5/25) and 20.0% (1/5) in women aged 38C40 years (NS); and 19.0% (4/21), 11.8% (2/17) and 1/1 (100%) in women aged 41C43 years (NS). Table?II Clinical outcomes of fresh, and warming cycles according to female age. The highest achieved cumulative ongoing pregnancy rate (62.5%) was obtained in the 34 years group. The ongoing clinical pregnancy rate showed a declining tendency with the increasing maternal age (Table?III). A significant difference was found between age group <34 years and age group 41C43 years (= 0.006). Table?III Cumulative ongoing pregnancy rate after the fresh cycle, first warming cycle and second warming cycle according to female age. According to the Cox regression analysis, infertility factors, basal FSH levels, stimulation protocols, number of retrieved COCs and MII, sperm Exherin IC50 quality and oocyte incubation time between retrieval and vitrification all did not influence the ongoing pregnancy rates. An inverse correlation was found between the maternal age >40 and the ongoing pregnancy rates (Table?IV). Table?IV Effect of patients and cycle characteristics on cumulative ongoing pregnancy based on Cox regression analysis (per patient basis). At the date of submission of this manuscript, 10 and 18 patients failed to complete the first and second warming cycle, respectively. The average numbers of available oocytes per patients are 5.22 2.41 (= 47) and 4.94 2.26 (= 89) for the first and second warming cycle, respectively. Moreover, 509 vitrified oocytes are still available in the pregnant patient group. Discussion Until recently, cryopreservation of human oocytes was regarded as an inconsistent and generally inefficient procedure; accordingly its application was restricted to very special situations where alternative solutions were not available (Porcu culture of oocytes without the protection of cumulus-corona radiata cells was decreased to minimal, and the culture period after vitrification Exherin IC50 was restricted to 2 h. Our previous work has investigated the performance of fresh and vitrified oocytes after insemination with ICSI. The vitrification procedure had no detectable effect on the developmental competence of oocytes. After ICSI and culture for 2 days, 52% of oocytes had developed to top quality embryos both from the fresh and vitrified group. This observation is confirmed by the present study where no statistical differences were found in the laboratory outcomes between fresh and vitrified oocytes. Although a negative trend was observed in the overall clinical outcomes when embryos derived from vitrified oocytes were transferred, the fresh and vitrified transfer groups cannot be compared in this study since the former group included all patients although the latter group included only those who did not become pregnant after the.