Objective: To verify whether microinjection into retrieved oocytes of motile spermatozoa with morphologically normal nuclei, strictly defined by high power light microscopy (x >6000), improves the IVF/intracytoplasmic sperm injection (ICSI) pregnancy rate in couples with repeated ICSI failures.
Design: Comparative prospective study testing routine IVF/ICSI outcome parameters against those of modified ICSI based on morphological selection of spermatozoa with normal nuclei.
Setting: Male factor fertility laboratory and IVF center.
Patient(s): Sixty-two couples, with at least two previous consequent pregnancy failed ICSI cycles, underwent a single ICSI trial preceded by morphological selection of spermatozoa with normal nuclei. Fifty of these couples were matched with couples who underwent a routine ICSI procedure at the same IVF center and exhibited the same number of previous ICSI failures.
Intervention(s): Standard ICSI and modified ICSI.
Main outcome measure(s): ICSI pregnancy rate.
Result(s): The matching study revealed that pregnancy rate after modified ICSI was significantly higher than that of the routine ICSI procedure (66.0% vs. 30.0%).
Conclusion(s): Microinjection into retrieved oocytes of selected spermatozoa with strictly defined morphologically normal nuclei improves significantly the incidence of pregnancy in couples with previous ICSI failures.