Assessment of maximal fertilization rates with intracytoplasmic sperm injection.

PURPOSE: Maximal fertilization rates following ICSI were assessed using two essential steps: immobilization of sperm and aspiration of oocyte cytoplasm. METHODS: ICSI procedure was performed for couples (N = 42) in whom the male suffered severe infertility or failure of fertilization in previous IVF cycle using different oocyte cytoplasmic aspiration and sperm immobilization methods. Outcome in four patient groups was measured by oocyte damage, fertilization rate, and pregnancy rate. RESULTS: Maximal fertilization (90%) were achieved from the group which used immobilization of sperm by hard-touching the tail with a pipette and optimal aspiration of oocyte cytoplasm. CONCLUSIONS: The results suggest that if the immobilization of sperm and aspiration of oocyte cytoplasm are handled right during ICSI, this procedure can be expected to yield a 90% fertilization rate.