Microassisted Fertilization of Human Oocytes with Intracytoplasmic Sperm Injection in In VitroFertilization Program

Moon, Shin Yong; Kim, Seok Hyun; Ryu, Buom Yong; Oh, Sun Kyung; Suh, Chang Suk; Choi, Young Min; Kim, Jung Gu; Lee, Jin Yong

Abstract

In spite of much progress in in vitro fertilization and embryo transfer(IVF-ET) program,the pregnancy rate remains at 20~30%, and the endometrial implantation rate per embryotransferred at 10%. Although IVF-ET is widely applied in the treatment of coupleswith male factor infertility, it may fail in many infertile couples with normal semen parameters,and certain couples cannot be accepted for standard IVF-ET due to unfertilization orextremely low fertilization rate of oocytes. Recently, several procedures of microassistedfertilization(MAF) using micromanipulation have been introduced, and pregnancies and birthshave been obtained after intracytoplasmic sperm injection(ICSI).This clinical study was performed to develop and establish ICSI as an effective procedureof MAF in infertile couples who could not be accepted for standard IVF-ET becauseof extremely impaired semen characteristics(Group A) and because of failure in fertilizationof extremely low fertilization rate of oocytes with the conventional fertilization technique inthe previous IVF-ET cycles(Group B). From March, 1995 to December, 1996, a total of 114cycles of IVF-ET with ICSI in 65 infertile patients were included in study group, and theoutcomes of ICSI were analyzed according to fertilization rate, cumulative embryo score(CES), and pregnancy rate.In Group A, 34 patients were evaluated with semen score such as number of totalmotile sperms, and then divided into 4 groups accordingly. In 62 ICSI cycles, the numberof oocytes retrieved after controlled ovarian hyperstimulation(COH) was 12.4+/-6.8, and thenumber of oocytes optimal for ICSI procedure was 8.8+/-5.5. The fertilization rate of 65.7+/-23.6% could be obtained after ICSI. The number of embryos transferred was 4.4+/-2.2 withthe mean CES of 50.5+/-34.3 in ICSI cycles. The overall pregnancy rate was 24.2%(15/62)per cycle and 44.1%(15/34) per patient. There were no significant differences in the pregnancyrates among 4 groups. Although more mature oocytes were retrieved, the fertilizationrate was significantly lower in Group A-1 compared with Group A-IV. However, semenscore did not clearly affect the outcomes of ICSI in couples with severe male factor infertility.In Group B, the number of oocytes retrieved after COH was 10.5+/-6.1 in 49 previouscycles, and 10.8+/-5.7 in 52 ICSI cycles. In ICSI cycles, the number of oocytes optimal forICSI procedure was 8.5+/-5.1 with the fertilization rate of 72.4+/-22.5%. The number ofembryos transferred was 1.4+/-2.4 in previous cycles, and 4.7+/-1.8 with the mean CES of 50.4+/-29.9 in ICSI cycles. In ICSI cycles, the overall pregnancy rate was 30.8%(16/52) percycles and 51.6%(16/31) per patients.In conclusion, MAF of human oocytes with ICSI is a promising fertilization method forIVF-ET patients, especially with few spermatozoa for the conventional methods of in vitroinsemination and with the past history of failure in fertilization or low fertilization rate inthe previous cycles, and ICSI using micromanipulation procedures applied to human oocyteswill provide a range of novel techniques which may dramatically improve the pregnancy ratein IVF-ET program and contribute much to the effective management of infertile couples.