Intracytoplasmic sperm injection (ICSI), in contrast to the conventional IVF procedures, may help attain a higher rate of normal fertilization in extremely low oocyte retrieval cycles. The results of the study have been published in the recent issue of the journal Fertility and Sterility. Yu-Che Ou from the Department of Obstetrics and Gynecology, Chang Gung Memorial Hospital, Taiwan, and colleagues, conducted a case-control study on infertile subjects with one to three oocytes per retrieval, and were divided into two groups undergoing either ICSI or IVF treatment. During the study, the cycle cancellation, fertilization, implantation and clinical pregnancy rates per transfer were observed. The study results are shown in the Table:
Although the rates of clinical pregnancy, implantation, and live births per transfer were higher in the ICSI group, the difference was not statistically significant between the two groups. Also, the cycle cancellation and complete fertilization failure rates were found to be similar in both the groups.Earlier, Requena, et al. (Journal of Assisted Reproduction and Genetics, 2000) conducted a prospective case-control study to evaluate maturation in vitro of human oocytes (MIVHO) as an alternate to IVF treatment, in low ovarian responders. Oocyte retrieval, maturation in vitro, fertilization, and blastocyst development rates were observed in spontaneously ovulatory women at the Instituto Valenciano de Infertilidad. The study results showed that the oocyte retrieval rate was considerably higher in cases where the pickup was carried out before follicular selection. The results of MIVHO in normal responders as well as low responders with an ovarian content of early antral follicles >5, were comparable. The study results demonstrated that MIVHO in low responders with an adequate number of early antral follicles could be successful and oocyte retrieval before follicular selection would aid in attaining more oocytes.
Although low ovarian response is not well defined, usually a patient with <34 oocytes, serum peak levels of <500mg/ml after aggressive stimulation, and with a background of at least two unsuccessful attempts of ovarian stimulation, is considered to be a low responder. Low ovarian reserve could be a result of high body mass index, pelvic adhesions, prior ovarian surgery, or progressive age. As the IVF outcome is directly dependent on the number of embryos available, low embryo count could result in decreased pregnancy rates.Though ICSI is associated with damage to a low percentage of injected oocytes, this micro-assisted fertilization technique is preferable in cases of oligospermia and azoospermia. Demonstrating the better performance of ICSI compared to IVF in very low oocyte retrieval cycles, the current study suggests ICSI as a superior choice for treating this condition.
References
1. Ou YC, Lan KC, Huang FJ, Kung FT, Lan TH, Chang SY. Comparison of in vitro fertilization versus intracytoplasmic sperm injection in extremely low oocyte retrieval cycles. Fertil Steril. 2008 Dec 22. [Epub ahead of print].
2. Requena A, Neuspiller F, Cobo AC, et al. The potential use of maturation in vitro of human oocytes in low responder patients. J Assist Reprod Genet. 2000 May;17(5):239-44
