THE INFLUENCE OF SUBZONAL MICROINSEMINATION OF OOCYTES FAILING TO FERTILIZE IN SCHEDULED ROUTINE IN-VITRO FERTILIZATION CYCLES

The subzonal microinsemination (SUZI) of oocytes failing to fertilize following routine in-vitro fertilization (IVF) insemination was studied in comparison to routine reinsemination. The data presented indicate that fertilization rate was significantly better with SUZI (23.4%) than with reinsemination (8.3%). The percentage of cleaved replaceable embryos generated was also significantly higher following SUZI than,vith reinsemination (96.6% versus 66.7% respectively). SUZI led to a significantly higher increase in the percentage of additional number of fertilized oocytes (100%), fertilization cycles (185%), embryos replaced (108%) and embryo replacement cycle over that generated by initial insemination. These were in comparison to 26, 14.3, 11.6 and 15%, respectively, as a result of reinsemination. No pregnancy occurred following replacement of embryos generated from reinsemination. Six pregnancies resulted from replacement of embryos following SUZI. We suggest therefore that SUZI should be the preferred option of practice when oocytes have failed to fertilize following initial insemination for routine IVF.