Higher Pregnancy Rate with Intrafallopian Tubal Gamete or Zygote Transfer (GIFT or ZIFT) than Intrauterine Embryo Transfer (IVF-ET)

From November 1996 to September 1998, we had treated infertile couples who required assisted reproductive conception by allocating to either one of the three treatment methods: IVF-ET for those with bilateral tubal obstruction; ZIFT for those with at least one tubal patency but poor sperm ; and GIFT for those with at least one tubal patency and normal sperm (unexplained infertility). The ovarian stimulation protocol was all the same by using GnRH analogue (Suprefact®) for pituitary suppression and daily hMG (Metrodin®) injection for ovarian stimulation. The oocyte pick up was due when the leading follicle reach 18 mm. For IVF-ET and ZIFT, the fertilization was obtained by conventional in vitro fertilization or by ICSI depending on the sperm quality. Laparoscopic intrafallopian tubal gamete or zygote transfer was preformed on day 0 ( ovum pick up day) for the GIFT or on day 1 for the ZIFT group. Intrauterine embryo transfer was performed on day 2- 3 for the IVF-ET group. Every treatment cycle was conducted by the investigator group to minimize the variation of technical bias. Of all the 213 treatment cycles, 82 were IVF-ET, 92 were ZIFT, and 39 were GIFT. The average female patient age in each groups was not different. The pregnancy rate achieved in the GIFT and ZIFT groups were significantly higher than the IVF-ET group ( 46.2%, 40.2% and 23.2% respectively , p < 0.05). For the pregnancy outcome, the abortion rate seemed to be highest in the IVF-ET group ( 36.8%) whereas the multiple pregnancy rate seemed to be higher in the fallopian tubal transfer group ( 27% for ZIFT and 38.9% for GIFT), although there were no statistical significance. The benefit of the higher pregnancy rate for the intrafallopian tubal transfer treatment group could be due to the more suitable environment for the early stage embryo and the the more synchronize of the endometrial receptivity and the embryo arrival timing provided by the fallopian tube. In conclusion, until the optimal in vitro embryo culture system can be developed, gamete and zygote intrafallopian tubal transfer should yield higher pregnancy rate than intrauterine embryo transfer