RESUMEN
OBJECTIVE: To compare the detection rate of multinucleation with the time-lapse system and conventional control timing proposed by European Society of Human Reproduction and Embryology (ESHRE) consensus and evaluate its impact on pregnancy rates. DESIGN: Retrospective study. SETTING: A private IVF center. PATIENT(S): A total of 686 embryos from 511 intracytoplasmic sperm injection (ICSI) cycles. INTERVENTION(S): None. MAIN OUTCOME MEASURE(S): A time-lapse system was used to acquire embryo images until ET; the stored data were reviewed for the presence and persistence of multinucleation. The detection rate of multinucleation was compared with ESHRE/ALPHA consensus-proposed embryo evaluating times (23 ± 1, 26 ± 1, 44 ± 1 hours). Morphokinetic characteristics of multinucleated embryos and the effect of multinucleation on pregnancy rate were researched. RESULT(S): Multinucleation was detected in 159 embryos of 145 ICSI cycles. Using ESHRE/ALPHA consensus embryo evaluating times, only 44 (27.6%) out of 159 multinucleated embryos could be identified. In cycles with multinucleated ETs compared with cycles with no multinucleated embryos, clinical pregnancy rates (respectively, 23.4 vs. 44) and implantation rates (respectively, 23.3 vs. 43.6) were significantly lower. Time to 2-cell, 4-cell, and 6-cell stage was significantly longer in multinucleated embryos. Patient age (odds ratio [OR], 0.95; confidence interval [CI], 0.92-0.98) and presence of multinucleation (OR, 0.37; CI, 0.24-0.56) were the only significant predictors of clinical pregnancy rate. CONCLUSION(S): The time-lapse monitoring system seems to be a valuable tool to identify all cases with multinucleation. We conclude that the detection of multinucleation by time-lapse monitoring is associated with lower implantation and clinical pregnancy rates.