The proportion of male factor infertility due to quantitative and qualitative sperm disorders is about 50%~60 in infertile couples. Although IVF-ET is widely applied in the treatment of couples with male factor infertility, it may fail in many
couples
with severe andrological problems, and certain couples cannot be even accepted for standard IVF-ET if the number of motile spermatozoa is too low. Recently, several procedures of microassisted fertilization(MAF) using micromanipulation have been
introduced, and pregnancies and births have been obtained after intracytoplasmic sperm injection(ICSI).
This clinical study was performed to develop and establish ICSI as an effective procedure of MAF using micromanipulation, and to apply ICSI clinically to infertile couples who could not be accepted for standard IVF-ET because of extremely
impaired
semen
characteristics such as<500,000 progressive motile spermatozoa present in the total volume of ejaculate. From March, 1995 to May, 1996, 39 cycles of IVF-ET with ICSI in 24 couples with severe male factor infertility were included in study group,
and the
outcomes of ICSI were analyzed according to fertilization rate, cumulative embryo score(CES), and pregnancy rate.
Patients were evaluated with semen score such as number of total motile sperms, and then divided into 4 groups accordingly : Group I with <5,000 normal motile sperms, Group II with 5,000~50,000, Group III with 50,000~500,000, and Group IV
with>500,000.
In 39 ICSI cycles, the number of oocytes retrieved after controlled ovarian hyperstimulation(CO-H) was 12.23±6.99, and the number of oocytes optimal for ICSI procedure was 10.07±5.62. The fertilization rate of 59.7±23.1% could be obtained
after
ICSI.
The number of embryos transferred was 4.26±2.22 with the mean CES of 50.7±30.5 in ICSI cycles. The overall pregnancy rate was 23.1%(9/39) per cycle and 37.5%(9/24) per patient with the clinical pregnancy rate of 15.4%(6/39) per cycle and
25.0%(6/24)
per patient. There were no significant differences in the pregnancy rates among 4 groups. Especially, although more mature oocytes were retrieved in Group I compared with Groups III and IV, the fetilization rate and the pregnancy rates were not
significantly different.
In conclusion, MAT of human oocytes with ICSI could be used successfully for IVFET in infertile couples who had few spermatozoa for the conventional methods of in vitro insemination, and sperm parameters did not clearly affect the outcomes of
ICSI
in
couples with severe male factor infertility. In addition, this development of gamete and embryo micromanipulation will lead to the new potentially exciting techniques such as enucleation for correction of polyspermy, and blastomere biopsy for
preimplantation genetic diagnosis.
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