Morphokinetic characteristics of embryos derived from in-vitro-matured oocytes and their in-vivo-matured siblings after ovarian stimulation.

RESEARCH QUESTION: Does delayed maturation of aspirated metaphase I (MI) oocytes, completed in vitro, adversely affect early embryo development? DESIGN: Time-lapse microscopy was used to compare morphokinetic variables between embryos derived from oocytes with delayed maturation after ovarian stimulation and from in-vivo-matured metaphase II (MII) sibling oocytes from the same IVF and intracytoplasmic sperm injection cycle. RESULTS: A total of 1545 injected oocytes in 169 cycles from 149 patients were included. The in-vitro-matured oocytes had lower normal fertilization rates than the MII aspirated oocytes (50.2% versus 68.0%; P < 0.001). Early key developmental events were significantly delayed in the normally fertilized in-vitro-matured compared with in-vivo-matured oocytes (polar body extrusion: 5.4 ± 3 versus 3.9 ± 1.8 h; P < 0.001; pronuclear fading: 27.2 ± 4.7 versus 25.1 ± 4.2 h; P < 0.001, respectively) and synchrony of the second cell cycle was adversely affected. The proportions of embryos with optimal second cell cycle length and second cell cycle were similar but with fewer top-quality embryos, based on an algorithm, for the delayed in-vitro-matured oocytes compared with their in-vivo-matured sibling oocytes (14% versus 29.1%; P < 0.001). CONCLUSIONS: Embryos derived from oocytes that failed to mature in-vivo in standard treatment after ovarian stimulation may show a different morphokinetic profile from their sibling oocytes aspirated at the MII stage after completing maturation in-vivo.

Prolonging oocyte in vitro culture and handling time does not compensate for a shorter interval from human chorionic gonadotropin administration to oocyte pickup.

OBJECTIVE: To assess the impact of oocyte aspiration, denudation, and sperm injection timing in relation to oocyte hCG exposure time on intracytoplasmic sperm injection (ICSI) outcome. DESIGN: Cohort study. SETTING: Tertiary medical center. PATIENT(S): A total of 614 consecutive ICSI cycles were performed in 421 patients aged <38 years with at least three aspirated oocytes and no more than three previous treatments. INTERVENTION(S): Gonadotropin-releasing hormone agonist or GnRH antagonist suppression; oocyte pickup (OPU)-hCG interval more/less than 36 hours; OPU-denudation interval more/less than 2 hours; denudation-ICSI interval more/less than 1 hour. MAIN OUTCOME MEASURE(S): Fertilization, embryo transfer, and pregnancy rates. RESULT(S): Late OPU was associated with more available embryos than early OPU and significantly higher rates of fertilization (66.0% ± 22.8% vs. 61.8% ± 24.3%), ET (99.5% vs. 96.2%), and pregnancy (47.2% vs. 35.4%). This advantage was more pronounced in GnRH agonist cycles. The length of incubation before or after denudation had no effect, regardless of OPU timing. On logistic stepwise regression, OPU timing was the only significant independent predictor of pregnancy (odds ratio 1.6, 95% confidence interval 1.17-2.29). CONCLUSION(S): The timing of OPU has a predominant effect on ICSI success, especially in GnRH agonist cycles. Delaying oocyte denudation or sperm injection does not compensate for insufficient postpriming exposure to the follicular environment.