Evaluation of the immature human oocytes from unstimulated cycles in polycystic ovary syndrome patients using a novel scoring system.

OBJECTIVE: To establish a novel scoring system for human immature oocytes and estimate its prognostic effects on the in vitro maturation (IVM) and developmental potential of human immature oocytes. DESIGN: Prospective study. SETTING: Hospital-based IVF center. PATIENT(S): Patients with polycystic ovary syndrome (PCOS) undergoing unstimulated cycles of oocyte retrieval. INTERVENTION(S): Immature (germinal vesicle and metaphase I) oocytes were collected from PCOS patients and were evaluated based on morphologic characters. After IVM, the maturation rate, fertilization rate, and cleavage rate were evaluated. The quality of the embryos and the apoptosis of the granulosa cells (GCs) were analyzed as well. MAIN OUTCOME MEASURE(S): Morphologic characters of immature oocytes and maturation rate, fertilization rate, cleavage rate, high-quality embryo formation rate, and the apoptosis of the GCs after IVM. RESULT(S): The maturation rate, fertilization rate, cleavage rate, and high-quality embryo formation rate of both MI and GV oocytes reduced with the decrease of the score. There were no differences in maturation, fertilization, and cleavage rates between the MI and GV phase. The apoptosis rate of GCs of grade 1' and 0' oocytes was obvious higher than those of grade 3-4'. CONCLUSION(S): Evaluating cumulus layer around the oocyte was a simple but useful method, which played an important role in terms of yielding good prognostic parameters in an embryology laboratory. The scoring system of immature oocytes can correctly reflect the development potential of human oocytes.