The in vitro maturation and maturation time of oocytes collected following in vivo hCG-priming in IVM/F-ET program are correlated with their cumulus cell pattern.

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Objective: Recently, Chian et al. (2000) reported that the higher maturation and pregnancy rates resulted from hCG-priming prior to oocyte collection in IVM program of women with POCS. This study was carried out to investigate whether the in vitro maturation and maturation time of oocytes collected following hCG-priming in IVM/F-ET program are correlated with their cumulus cell (CC) pattern. Design: Cumulus-oocyte complexes (COCs) were collected after only hCG-priming to women with high risk of OHSS undergoing IVM/F-ET program and were divided into three groups according to their CC pattern. The maturation and fertilization rates of oocytes, the cleavage rate of zygotes, and time course of maturation were compared with among these groups. Materials/Methods: A total of 70 IVM/F-ETs were performed in 57 patients (mean age: 32.5 ± 3.1 years). All patients had experience with OHSS before. The patients were primed with 10,000 IU of hCG about 36 hours before oocyte collection. A transvaginal ultrasound machine with 19-gauge aspiration needle was used to aspirate follicles between 5 and 14 mm in diameter. The aspirates were filtered with 70-mm (in hole size) mesh and washed with medium, and then COCs were isolated under a stereomicroscope. The normal COCs were divided into three groups according to their CC pattern: group 1, oocytes with dispersed CC; group 2, oocytes with multilayered CC; group 3, oocytes with sparse CC. The maturity of oocytes was evaluated, and the immature oocytes were then cultured in maturation medium, YS medium with 30% human follicular fluid supplemented with 1 IU/ml FSH and 10 IU/ml hCG. During culture, the maturity of the oocytes was also determined at 6, 30, 42 and 54 hours. Conventional IVF or ICSI was performed in all mature oocytes, and the resulting embryos were transferred on day 2 or 3 after insemination or ICSI. Results: The atretic and/or ruptured COCs were 6.9% (95/1386, discarded), while the proportion of COCs in group 1, 2 and 3 was 33.2% (460/1386), 38.8% (538/1386) and 21.1% (293/1386), respectively. The maturation rate until 30 hours of culture in group 1, 2 and was 83.3% (383/460), 32.7% (176/538), and 66.2% (194/293), respectively. The maturation rate until 42 hours of culture in group 1, 2 and 3 was also 88.9% (409/460), 60.4% (325/538), and 72.0% (211/293), respectively. Finally, the maturation rate (88.9%, 409/460) until 54 hours of culture in group 1 was significantly higher than those of group 2 (66.3%, 339/538) and group 3 (72.4%, 212/293) (P < 0.001). There were no significant differences in the rates of 2PN and cleavage among these three groups. In these 70 cycles of in vivo hCG-priming IVM/F-ET program, 25 cycles (35.7%) became clinically pregnant and 21 pregnancies are ongoing (30.0%). Conclusions: These results suggest that there should be a positive correlation between the presence of dispersed CC at the time of oocyte collection and the ability of the oocytes to mature in in vivo hCG-priming IVM/F-ET program. In addition, it was found that there was correlation between CC pattern and the maturation time of oocytes. Further studies are necessary to elucidate the differences of the ability of oocytes to mature and to develop in accordance with the CC pattern of COCs collected in in vivo hCG-priming IVM/F-ET program. Supported by: Maria Women’s Hospital.