A novel system for in vitro maturation of human oocytes.

OBJECTIVE: To compare in vitro maturation of cumulus-free oocytes in glucose-free medium (P1) and standard medium (TC199). DESIGN: Prospective, cohort study. SETTING: Assisted reproductive technology program. PATIENT(S): One hundred eight patients undergoing ICSI. INTERVENTION(S): Germinal vesicle-stage or metaphase I--stage oocytes were allocated to culture with P1 or TC199. Metaphase II oocytes were fixed for immunofluorescence analysis or fluorescence in situ hybridization at 24 or 48 hours (or both). Media were compared by performing conditional logistic regression analysis that controlled for egg-specific factors. MAIN OUTCOME MEASURE(S): Proportion of mature oocytes and appearance of normal spindle-chromosome cytoarchitecture. RESULT(S): At 24 hours, more P1 oocytes than TC199 oocytes reached metaphase II (59.7% vs. 44.9%). At 48 hours, 71.7% of P1 oocytes and 61.0% of TC199 oocytes reached metaphase II, but this difference was not significant. Metaphase II oocytes in P1 were 34.3% more likely than those in TC199 to have a bipolar spindle with aligned chromosomes. Compared with oocytes at the germinal vesicle stage at 0 hour, those at metaphase I at 0 hour were more likely to progress to metaphase II (72.6% vs. 46.1% at 24 hours; 84.1% vs. 60.6% at 48 hours). CONCLUSION(S): P1 is superior to TC199 for in vitro maturation of granulosa-free human oocytes.

The number of eight-cell embryos is a key determinant for selecting day 3 or day 5 transfer.

OBJECTIVE: To select patients for day 3 vs. day 5 embryo transfer. DESIGN: Retrospective analysis of assisted reproduction technology (ART) cycles comparing outcomes of day 3 and day 5 transfers. SETTING: ART program of Brigham and Women's Hospital. PATIENT(S): Patients with day 3 or day 5 embryo transfers (n = 221 and 141, respectively). INTERVENTION(S): Cycles with eight or more zygotes were stratified by the number of eight-cell embryos available on day 3 (none, one or two, or three or more). MAIN OUTCOME MEASURE(S): Number of blastocysts, implantation rates, ongoing pregnancy rates, and number of fetal heart beats. RESULT(S): With no eight-cell embryos on day 3, 0% and 33% pregnancies resulted from day 5 vs. day 3 transfers. With one or two eight-cell embryos on day 3, ongoing and high order multiple rates were not different between day 3 and day 5 transfers. With three or more eight-cell embryos, day 5 transfer resulted in a decrease in multiple gestations but no difference in ongoing pregnancy rates compared with day 3 transfer. CONCLUSION(S): With no eight-cell embryos on day 3, a day 3 transfer is warranted. With one or two eight-cell embryos, any benefit of day 5 transfer appears to be equivocal. With three or more eight-cell embryos, day 5 transfer is recommended.

Assessment of nuclear and cytoplasmic maturation in in-vitro matured human oocytes.

BACKGROUND: With improved prospects for the use of human oocyte in-vitro maturation in assisted reproductive technologies, the need to define more clearly the coordination of nuclear and cytoplasmic maturation has arisen. METHODS: Immunofluorescence and confocal microscopy were used to evaluate cell cycle-dependent modifications in chromatin and microtubules in human germinal vesicle oocytes (n = 455) undergoing in-vitro maturation. RESULTS: Four distinct classes of germinal vesicle stage oocytes were identified based on the expression of G2/interphase characteristics, but, of these, only one class of oocytes was competent to complete meiotic progression to metaphase-II in vitro. The majority of germinal vesicle stage oocytes resumed meiosis within 6 h (88.9%) of culture and exhibited an accelerated pace of progression to metaphase-II (66.7%) over 24 h, but in general were unable to maintain meiotic arrest and defaulted into interphase within 24 h of polar body emission. Characterization of microtubule dynamics and chromatin phosphorylation demonstrates specific cell cycle deficiencies in in-vitro matured human oocytes. CONCLUSION: This work forms a basis for future studies aimed at optimizing nuclear and cytoplasmic maturation during in-vitro maturation.