[Statistical correlation between a transference test and embryonic transference in an assisted reproduction program]. / Correlación estadística entre una prueba de transferencia y la transferencia embrionaria en un programa de reproducción asistida: análisis de los resultados.

OBJECTIVE: Determining if a statistical correlation can be established between those variables observed during the transference test performed before ovarian stimulation and those obtained during the real embryo transference. TYPE OF STUDY: Clinical retrospective. MATERIALS AND METHODS: Ninety four female patients included in the IVF-ET were studied and a transference test previous to ovarian stimulation was performed. The following parameters were considered in this test: hysterometry, type of catheter, degree of difficulty, and person performing it. A total of 117 embryonic transferences were carried out, and the same parameters observed during the test were measured. The chi square test was used for the statistical analysis. RESULTS: The most commonly used kind of catheter was the Cook Soft Pass (n = 92), and a statistically significant correlation was observed with the one used during the real transference (n = 94). Concerning the degree of difficulty, the transference test resulted complicated in 4.2% of the cases, difficult in 31.6% of them, and easy in 64.2% of them, presenting a statistical correlation with the real transference, where the procedure resulted complicated in 1.7% of the patients, difficult in 32.4% of them, and easy in 65.8%. In addition, and with the intention of ruling out the medical factor, we tried to have the same person performing the transference test and the real procedure, and a statistically significant correlation was also observed. Pregnancy rate per transference was 27.4%. When an association between the difficulty of a real transference and pregnancy rates was tried, no statistical association between an easy or a difficult transference was observed. CONCLUSIONS: Embrionic transference is a fundamental phase for IVF-ET programs. However, a variety of factors can influence this procedure, some are medical and others are mechanical. Our results allow us to conclude that there is a statistical correlation between those variables observed during the real embryonic transference and the test, so the latter can be considered as a very useful element in the integral in vitro fertilization process, which prevents the real transference from becoming a blind procedure.

Falla inesperada en la fertilización in vitro convencional: reinseminación con ICSI o indicación de ICSI en ciclos subsecuentes / Unexpected failed fertilization in vitro: ICSI reinsemination or ICSI indication for subsequent cycles

The objective was to determine if intracytoplasmatic sperm injection (ICSI) for "rescue" of unexpected failed conventional insemination should be carried out for therapeutic or diagnostic purposes, that is, as a predictor for performing ICSI as a standard treatment in subsequent cycles. A retrospective clinical study was carried in 26 patients who showed unexplained fertilization failure on a first conventional IVF attempt, and reinsemination by ICSI was performed. We compared these results with those of 13 of the 26 patients who underwent a second attempt in which ICSI was used as the only insemination technique. A fertilization rate of 46.27 was achieved with reinsemination by ICSI but none resulted in pregnancy (0). Fertilization was achieved with ICSI in all patients with previous fertilization failure and a pregnancy rate of 38.46. Patient characteristics, cycle characteristics, sperm parameters or oocyte quality did not differ significantly between two groups. In conclusion, the ICSI reinsemination technique can give good fertilization rates but the potential of the generated embryos to achieve pregnancy seems to be low. In addition, it can be demonstrated that these patients have good possibilities of obtaining a pregnancy in a following cycle using ICSI.