Intracytoplasmic sperm injection facilitates fertilization even in the most severe forms of male infertility: pregnancy outcome correlates with maternal age and number of eggs available.

OBJECTIVE

To evaluate, in a prospective study, the fertilization and pregnancy rates after intracytoplasmic sperm injection (ICSI) in infertile couples with severe male infertility.

DESIGN

Intracytoplasmic sperm injection was performed in 229 consecutive IVF cycles on 190 couples with rigorously defined severe male infertility or proven failure of fertilization in prior IVF cycles. Neither male nor female partners were chosen from a waiting list or on any other selective basis, including age, prior or anticipated ovarian response, or oocyte number or quality. There were no upper age limits, in no instance was donor sperm used for ICSI, and cycle cancellation rate was minimal.

SETTING

Private genetics and fertility center in Fairfax, Virginia.

MAIN OUTCOME MEASURES

Fertilization, transfer, and pregnancy rates were measured in ICSI-treated couples, and comparisons were made regarding both female age and strictly defined semen categories.

RESULTS

Two hundred six cycles (90%) resulted in ETs, with initiation of 52 pregnancies (25% per transfer, 23% per cycle). Thirty-eight of 52 (18% per transfer) were clinical pregnancies with established gestational sacs or were ongoing or delivered. Pregnancies were achieved even in older women but were more readily established in younger women producing larger numbers of metaphase II oocytes. The severity of semen abnormalities had some small effect on fertilization rate, but only actual necrospermia was associated with markedly decreased frequency of embryo formation. Pregnancy per transfer was similar across groups. In some cases, pregnancy was initiated with fewer than 100 viable sperm in the ejaculate.

CONCLUSIONS

Intracytoplasmic sperm injection is a very powerful new treatment for severe male infertility. Paradoxically, egg number and probably egg quality are now the main determinants of success in treating male infertility.