Two-step consecutive transfer of early embryos and blastocysts.

To evaluate and confirm the merit of two consecutive transfer attempts of early embryos and blastocysts. A total of 685 patients underwent routine 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). 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. 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; : 133-137).