A prospective randomized crossover comparison of zygote intrafallopian transfer and in vitro fertilization-embryo transfer in unexplained infertility.

60 couples aged under 38 with unexplained infertility were recruited in this prospective randomized crossover study to compare the efficacy of treatment between ZIFT and IVF-ET. A total of 150 stimulation cycles were commenced and 132 proceeded to successful egg collection (88%). Fertilization successfully occurred in 114 cycles (86.36%). A total of 110 embryo replacements were carried out, (52 uterine transfer and 58 tubal transfer). This prospective randomized cross over trial demonstrated the trend for higher implantation rate, pregnancy rate, and ongoing pregnancy rate with ZIFT over IVF-ET for patients with unexplained infertility. The actual implantation rate, pregnancy rate, and ongoing pregnancy rate with ZIFT were 13.7, 34.5, 31.0 per cent respectively compared to the results from IVF-ET which were 12.1, 26.9, 25.0 per cent respectively. However, the difference was not statistically significant. Although this study showed a 5 per cent ectopic pregnancy rate with ZIFT and none with IVF-ET, the difference was not statistically significant. Similarly, there was no difference in the overall miscarriage rate and multiple pregnancy rate between the two protocols. In conclusion, this prospective randomized crossover trial demonstrated the trend for higher reproductive outcomes in term of implantation rate, pregnancy rate, and ongoing pregnancy rate with ZIFT over IVF-ET in unexplained infertility but the difference was not statistically significant.