Comparación entre el clivaje temprano y el estadio pronuclear como parámetros de referencia para inducir el embarazo en pacientes ovoreceptoras en Cali (Colombia)

introduction: some authors have proposed that non-invasive embryo implantation methods (based on early cleavage or pronuclear stage for two cells 25 and 27 hours post-insemination) are applicable to in vitro fertilisation programmes, thereby increasing the probability of implantation and pregnancy. objective: comparing pregnancy rates in patients implanted with embryos originating from early cleavage to those from the pronuclear stage. methodology: a retrospective cohort study was carried out. embryo implantation patients were included who had been attending the fecundar -biomedicine centre in cali, colombia, from april 2004 to december 2007 who presented a poor responsetothecontrolledovarianstimulationcycle, age factor and/or ovarian failure and pregnancy substitute patients. the sample consisted of 45 patients; 36 patients (79%) were expected to become pregnant in the early-syngamy and cleavage group (group 1) and 9 patients (21%) in the pronuclear group (group 2). implantation and pregnancy rates were determined and the chi-square (x2) test was used for comparing both groups. results: 183 of the 289 zygotes complied with the proposed parameters (i.e. embryos from early cleavage, syngamy and pronuclear stage 25 and 27 hours post-insemination); 79% of these 183 came from the early cleavage and syngamy stage and 21% from the pronuclear stage. three embryos on average were transferred to embryo implantation patient; average age was 38, the pregnancy rate obtained when transferring early cleavage embryos was 44% compared to 41% for non-cleaved embryo transfer 25 hours post-insemination. no statistically significant differences were found regarding how pregnancy was induced. conclusion: equal success rates were obtained for both procedures in the given study conditions.