ABSTRACT
PURPOSE: In in vitro maturation (IVM) cycles primed with human chorionic gonadotropin (hCG), both immature and mature oocytes are retrieved from antral follicles sized 8-12 mm. Using time-lapse microscopy, we compared the morphokinetic behavior of embryos developed from oocytes matured in vivo and in vitro, testing the hypothesis that IVM affects preimplantation development. Furthermore, we extended the morphokinetic analysis of these embryos by a comparison with embryos obtained in stimulated assisted reproduction technology (ART) cycles. METHODS: In IVM cycles primed with follicle-stimulating hormone (FSH)/hCG, prior to sperm microinjection, oocytes surrounded by an expanded cumulus at retrieval and presumably mature (EC-MII) were incubated for 6 h, while immature oocytes enclosed in a compact cumulus (CC) were matured in vitro for 30 h. The morphokinetics of embryos selected for transfer or cryopreservation, derived from EC-MII and CC oocytes, were comparatively and retrospectively analyzed in terms of cleavage times (t2, t3, t4, t5, and t8) and intervals (cc2, cc3, s2, s3). For further comparison, the morphokinetics of embryos selected for transfer or cryopreservation (ICSI) or giving rise to ongoing pregnancies (model) in stimulated ART cycles was also assessed. RESULTS: The morphokinetic behavior of EC-MII and CC embryos was entirely comparable, as suggested by the absence of statistical differences in the averages of all cleavage times and intervals. Almost all cleavage and interval times were also similar between EC-MII, CC, ICSI, and model groups, with the exception of t4 and s2, which were delayed and longer, respectively, in embryos generated in IVM cycles (EC-MII and CC). CONCLUSIONS: These findings do not support the hypothesis that maturation in vitro affects embryo morphokinetics, while they suggest only marginal differences in the morphokinetics of embryos developed from oocytes matured in vivo and in vitro in IVM cycles and embryos developed from mature oocytes recovered in stimulated cycles.
Subject(s)
Embryonic Development/drug effects , Follicle Stimulating Hormone/administration & dosage , In Vitro Oocyte Maturation Techniques , Oocytes/growth & development , Adult , Chorionic Gonadotropin/administration & dosage , Cryopreservation , Embryo Culture Techniques/methods , Embryo Transfer/methods , Female , Fertilization in Vitro , Follicle Stimulating Hormone/metabolism , Humans , Oocytes/drug effects , Ovarian Follicle/drug effects , Ovarian Follicle/growth & development , Pregnancy , Pregnancy Rate , Reproductive Techniques, Assisted , Sperm Injections, IntracytoplasmicABSTRACT
PURPOSE: The aim of this retrospective study was to compare the competence of oocytes obtained from preovulatory and antral follicles. METHODS: Mature oocytes from preovulatory follicles were retrieved from women selected for standard IVF treatment (Group A). Mature oocytes from antral follicles were recovered from women undergoing hCG-primed in vitro maturation (IVM) treatment (Group B). Patients groups were matched for age, BMI, FSH, AMH and antral follicle count (AFC) values. In vivo matured oocytes from both groups were microinjected and resulting embryos were culture and selected on day 3 for embryo transfer. RESULTS: Oocyte pick-ups (OPU) were 315 and 204 in Groups A and B, respectively. Fertilization rates were comparable (72.8 and 75.9 %, respectively; P = 0.137). In Group A, in which the average number of embryos transferred was higher, clinical pregnancy rates per OPU (37.5 %) and embryo transfer (38.4 %) were superior in comparison to Group B (27.0 %, P = 0.013; 29.4 %, P = 0.041; respectively). On the other hand, implantation rates (Group A, 23.7 %; Group B, 20.8 %) and proportions of babies born per transferred embryo (Group A, 19.5 %; Group B, 16.9 %) were similar (P = 0.528 and 0.332, respectively). CONCLUSIONS: Overall, this suggests that oocyte competence is already achieved at the antral stage of follicle development.
