Papers by A. Gustavo Martinez
Objective: This study aimed to compare the use of semi-rigid and flexible catheters in terms of p... more Objective: This study aimed to compare the use of semi-rigid and flexible catheters in terms of pregnancy rate and level of difficulty of the embryo transfer (ET) procedure. Methods: Seven hundred and thirty-nine consecutive follicular aspirations for IVF or ICSI performed in our private fertility clinic within a 30-month period were randomly divided into two groups. Patients were allocated to either of the groups at the time of follicular retrieval with the aid of a random number generator according to the catheter used in ET: Group 1 (n = 370) -Frydman Classic Catheter 4.5 catheters; and Group 2 (n = 369) -Frydman Ultrasoft 4.5 catheters. Only patients offered ET in the randomized cycle were included (Group 1 = 363 and Group 2 = 340). Patients did not change groups after catheter allocation. Statistical analysis was carried out using an unpaired t-test or a chi square test as appropriate. Differences with P<0.05 were considered. Results: A statistically significant difference in favor of the use of the Ultrasoft catheter was evident for parameters use of a tenaculum (19.8% vs. 5.9%) or a hysterometer (5.0% vs. 1.2%), presence of blood during post-ET inspection of the catheter (9.9% vs. 3.8%), and implantation rate (13.0% vs. 16.4%). Clinical pregnancy and delivery rates were comparable in both groups. Conclusions: Our results suggest that a softer catheter may help with difficult ETs. Softer catheters, as also reported by other authors, resulted in better implantation rates.
The purpose of this study was to evaluate different cryopreservation protocols for in vitro-produ... more The purpose of this study was to evaluate different cryopreservation protocols for in vitro-produced ovine embryos and assess the survival rate after cryopreservation. The experiment was also designed to examine whether this technique is feasible to apply in large-scale operations. In a first experiment, ovine embryos cryopreserved in ethylene glycol using 3 steps (E-3S) showed a higher hatching rate and nuclei number than freezing with glycerol in 3 steps (G-3S) (40.0% versus 20.0% and 135.4 ± 20.7 versus 118.5 ± 19.5, respectively). In a second experiment, vitrification with ethylene glycol + Ficoll 70 + sucrose (EFS) recorded a higher hatching rate and nuclei numbers than vitrification with propylene glycol + glycerol (Pg + Gly) (51.1% versus 31.1% and 133.8 ± 36.8 versus 113.5 ± 22.0, respectively). In a third phase, vitrification of embryos with ethylene glycol + glycerol (Eg + Gly) resulted in higher development and hatching rates and nuclei number than EFS (87.3% versus 65.4%; 76.4% versus 54.5% and 135.7 ± 34.5 versus 113.1 ± 14.1, respectively). In a fourth experiment, fresh in vivo embryos produced a higher lambing rate (67.8%) than the other methods, and E-3S in vitro resulted in lower lambing rates (23.0%). E-3S in vivo, Eg + Gly in vivo, fresh in vitro and Eg + Gly in vitro recorded similar lambing rates (42.8, 37.5, 37.5 and 26.6%, respectively). Ewes receiving in vitro-produced ovine embryos resulted in higher assisted births and perinatal losses than those receiving in vivo-produced embryos (3.6% versus 16.9% and 1.2% versus 10.1%, respectively). Results demonstrate that the transfer of in vitro-produced embryos vitrified with Eg + Gly could have wide application, if the negative side effects of the produced offspring can be managed. 8
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Papers by A. Gustavo Martinez