The influence of number of embryos transferred on pregnancy outcome in women undergoing in vitro fertilization and embryo transfer (IVF-ET).

The purpose of this study was to retrospectively examine the influence of number of embryos transferred on pregnancy outcome in women undergoing in vitro fertilization and embryo transfer (IVF-ET) between July 1990-December 1991 at the Royal Free Hospital, London, United Kingdom. This study included three groups of patients: group 1-the number of embryo used for transferring was one embryo, group 2-the number of embryos used for transferring was two embryos and group 3-the number of embryos used for transferring was three embryos. This study demonstrated that the clinical pregnancy rate increased significantly when transferring two or three embryos compared to one. But this rate did not differ significantly when two embryos were compared with three embryos. The multiple pregnancy rate, miscarriage rate, and ectopic pregnancy rate did not differ significantly among the three groups studied but there was a risk of higher order multiple pregnancy if more embryos were transferred. In this study we found 3 triplets out of 35 pregnancies when 3 embryos were transferred (Group 3). In conclusion, this study demonstrates that when two or three embryos were transferred the clinical pregnancy rate increased significantly. Transferring two embryos instead of three did not alter the pregnancy rate. Moreover, triplets pregnancies were eliminated. Therefore, we suggest limiting the number of embryos to be transferred at two and the supernumerary embryos should be cryopreserved for future transfer.

Effect of maternal age on clinical outcome in women undergoing in vitro fertilization and embryo transfer (IVF-ET).

The purpose of this study was to assess the effect of age of IVF success in women undergoing in vitro fertilization and embryo transfer by comparing IVF outcome in two groups of patients: group 1-age < or = 35 years old and group 2-age > 35 years old. This retrospective study covered a one year period between January 1991-December 1991 and included 230 patients with 634 treatment cycles. The patients' mean age was 32 +/- 1.9 (range 20-38 years old). Inclusion criteria for treatment of patients with IVF-ET included patients with tubal disease and non-tubal disease who have failed conventional treatments. The majority of patients had infertility from tubal damage, unexplained infertility, and male infertility. This study showed that all pregnancy rates, ongoing pregnancy rates and implantation rates were found to be higher in the < or = 35 year old group. The pregnancy rate per ET, ongoing pregnancy rate and implantation rate were found to be 35.17, 27.58, 16.53 per cent respectively; while in the > 35 year old group, the pregnancy rate per ET, ongoing pregnancy rate, implantation rate were found to be only 17.93, 11.03, 8.07 per cent respectively. The miscarriage rate tended to be higher in the > 35 year old group (34.62%) compared to 15.69 per cent found in < or = 35 year old group. Multiple pregnancy rate and ectopic pregnancy rate were found to be 17.65 and 5.89 per cent respectively for the < or = 35 year old group but only 7.69, 3.85 per cent respectively for the > 35 year old group. From the statistical analysis comparing the outcome of pregnancy in these two groups, the pregnancy rate per ET, implantation rate, ongoing pregnancy rate and miscarriage rate were found to have statistical difference with P < 0.05. However, multiple pregnancy rate and ectopic pregnancy rate did not show any statistical significance in these two groups (P > 0.05). In conclusion, the results of this study indicated that maternal age especially when greater than 35 years old adversely affects clinical pregnancy and the spontaneous abortion rate.

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.