P-9: Single oocyte retrieval - to ICSI or not to ICSI?

Abstract

To investigate the efficacy of Intracytoplasmic Sperm Injection (ICSI) versus conventional in-vitro fertilization (IVF) in cycles with normal sperm parameters where only a single oocyte is available for insemination. Retrospective analysis. 311 low responder patients (425 cycles) undergoing assisted reproduction treatment between the years 2001-2005 at the IVF Unit at the Sheba Medical Center. Patients underwent either stimulated or spontaneous IVF cycles that resulted in single oocyte retrieval. ICSI was indicated after repeated fertilization failure, or in the presence of sub-fertile sperm samples. Fertilization and pregnancy rates were analyzed according to age (≤39 or >39), quality of sperm used (fertile or sub-fertile) and whether ICSI or conventional IVF were applied. In cases of fertile semen samples, ICSI and standard microinsemination produced similar fertilization rates (age ≤39: 75% vs. 67.1% respectively, P = 0.3244; age>39: 82.4% vs. 68.4%, P = 0.194). When pregnancy rates using fertile sperm were compared between ICSI and conventional IVF, no statistical significance was observed (age ≤39: 0% vs. 8.2% respectively, P = 0.1723; age>39: 0% vs. 1.1% respectively, P = 0.8482). Moreover, no pregnancies were achieved when ICSI was applied. Conversely, in cases of sub-fertile semen samples, ICSI was significantly superior to conventional IVF: for the younger aged group, fertilization rates were enhanced when ICSI was performed (85.4% vs. 44.2% respectively, P = .0001); for the older group, ICSI again produced higher fertilization rates (84.0% vs. 52% respectively, P=.0003) and higher pregnancy rates (8.0% vs. 0% respectively, P = .0238). Our results suggest that ICSI is not indicated when a single oocyte is retrieved and sperm analysis is normal. However, as expected, ICSI was found to be superior to conventional IVF when the semen sample fails to meet threshold criteria. We can therefore recommend from our preliminary results that ICSI should be applied only with the availability of subfertile sperm.