Sperm characteristics and outcome of human assisted fertilization by subzonal insemination and intracytoplasmic sperm injection*

Objective

To investigate the influence of sperm characteristics on the treatment by subzonal insemination (SUZI) and intracytoplasmic sperm injection of couples with severe male infertility.

Design

A retrospective analysis of 300 consecutive cycles of assisted fertilization concerning 202 infertile couples was performed. One hundred fifty-three couples underwent 362 unsuccessful IVF cycles, whereas on 49 couples IVF was not performed because of poor sperm characteristics.

Setting

Procedures were performed in an institutional research environment.

Patients, Participants

Couples in which the male partner was the presumed cause of repeated failure to achieve conception by IVF or in which seminal parameters were unacceptable for IVF.

Interventions

Three hundred transvaginal oocyte retrievals were performed after superovulation by GnRH agonist and gonadotropins.

Main Outcome Measures

After SUZI and intracytoplasmic sperm injection the following parameters were evaluated: fertilization, cleavage, pregnancy, and implantation rates in relation to the sperm parameters and the proportion of acrosome-free spermatozoa after different treatments.

Results

Normal fertilization occurred in 18% of the oocytes treated by SUZI and in 44% after intracytoplasmic sperm injection. Only the treatment by electroporation showed a positive correlation with the fertilization rate. Fourteen pregnancies were obtained after SUZI, 8 pregnancies after intracytoplasmic sperm injection, and 8 pregnancies after a combination of the two procedures. A score calculated from the sperm parameters after selection correlated with the fertilization obtained after SUZI, whereas a score calculated from the parameters before sperm selection correlated with the pregnancy rate. Sperm morphology influenced the implantation rate of the embryos obtained with these two procedures.

Conclusions

Intracytoplasmic sperm injection and SUZI can successfully treat couples who fail IVF or who cannot benefit from IVF. Different treatments can be applied to semen samples to increase the number of acrosome-reacted spermatozoa. The few significant relations found between sperm characteristics and the outcome of assisted fertilization cannot predict the outcome.