Intracytoplasmic sperm injection. Survey of world results

The widespread application of intracytoplasmic sperm injection (ICSI) has raised concern about the efficacy and safety of this novel technique. The European Society of Human Reproduction and Embryology (ESHRE) has established an ICSI Task Force to collect annually the clinical results, the outcome of pregnancy, and the follow-up of children after ICSI using ejaculated, epididymal, and testicular sperm in order to address these important issues in a relatively short time. Over a 3-year span (1993-1995), the number of centers for ICSI increased from 35 to 101, and the total number of ICSI cycles per year rose from 3,157 to 23,932. The incidence of oocytes damaged by the procedure remained low (< 10%), whereas the fertilization rates obtained with ejaculated, epididymal, and testicular spermatozoa for 1995 were 64%, 62%, and 52%, respectively. Thus, 86-90% of the couples had embryo transfer, and the viable pregnancy rate was 21% for ejaculated, 22% for epididymal, and 19% for testicular sperm, while the incidence of multiple gestations was 29%, 30%, and 38%, respectively. It is noteworthy that no difference was found in ICSI results concerning the etiology of azoospermia, for example, obstructive (congenital or acquired) or nonobstructive. Furthermore, 3,149 transfers of frozen-thawed embryos after ICSI with ejaculated, epididymal, or testicular sperm were performed, and in 11%, 9%, and 7% of them, respectively, a viable pregnancy was achieved. The ICSI results were similar during this 3-year period, irrespective of the origin of the sperm. The perinatal outcome of children born after ICSI was not different from that after in vitro fertilization or natural conception and was only affected by multiplicity. Moreover, the incidence of major or minor malformations was not increased, but the chromosomal, especially the sex chromosomal, aberration rate was slightly elevated (approximately 2%). Therefore, ICSI has opened new horizons in the treatment of male infertility. The achievement of pregnancy after ICSI using ejaculated, epididymal, or testicular sperm is very satisfactory. The procedure seems to be safe, but further follow-up of the children is necessary to more accurately assess its safety.