Abstract
Aim: To evaluate and confirm the merit of two consecutive transfer attempts of early embryos and blastocysts. Methods: A total of 685 patients underwent routine in vitro fertilization (IVF) cycles. The study population consisted of three groups: (i) Group 1, early stage embryos were transferred (460 patients; 567 cycles); (ii) group 2, blastocysts were transferred (88 patients; 105 cycles); and (iii) group 3, a two-step (consecutive) transfer was performed on 137 women (141 cycles). Specifically, a standard embryo transfer was performed on day 3, together with a two-step (consecutive) transfer of blastocysts. After the early embryo transfer, an extended culture of supernumerary embryos was conducted, followed by a second transfer of blastocyst(s). Results: No significant differences were found in the three groups with regards to either pregnancy or implantation rates for groups 1, 2, or 3; pregnancy: 34.6, 29.9, and 33.6%, respectively; implantation: 18.6, 15.9, and 15.1%, respectively. The miscarriage rate for each group was also not significant; 20.4, 30.8 and 28.6% for groups 1, 2 and 3, respectively. The multiple pregnancy rate of the three groups was 30.4, 30.8 and 35.7%, respectively, and these were not found to be significant results. Conclusion: No significant difference was found between the three groups with regards to the pregnancy, implantation, multiple pregnancy and miscarriage rates. The multiple pregnancy rate was highest in the two-step (consecutive) transfer group. This difference was not regarded to be highly significant. (Reprod Med Biol 2003; 2: 133-137).