Effects of ovarian source, patient age, and menstrual cycle phase on in vitro maturation of immature human oocytes

Objective: To determine the efficiency of in vitro maturation, expressed by nuclear maturation, of oocytes aspirated during gynecologic surgeries or collected from excised ovaries. To assess the effect of patient age and cycle phase at collection on the oocyte's ability to mature in vitro. To examine the time course of oocyte maturation in vitro. Design: Nuclear maturation based on patient criteria compared. Setting: University-based IVF program and research center. Patient(s): Consented patients undergoing gynecologic surgeries or patients undergoing oophorectomy. Intervention(s): Oocytes were maintained in culture for 48 hours and evaluated for maturation. Main Outcome Measure(s): Nuclear maturation evaluated as germinal vesicle breakdown (GVBD) or progression to the metaphase II (MII) stage. Result(s): A significantly higher percentage of oocytes collected during the follicular phase of the menstrual cycle underwent GVBD than did oocytes collected during the luteal phase (60% versus 48%, respectively). The percentage of oocytes reaching the MII stage, from these two groups, was not different. No statistically significant differences in maturation were observed in oocytes from different ovarian sources or from patients >40 or <40 years of age. Conclusion(s): These data suggest that oocytes collected during the follicular phase are more likely to undergo GVBD than oocytes collected during the luteal phase. In this study, ovarian source, age, or cycle phase did not influence the final meiotic maturation of oocytes to metaphase II.