Objective: To explore the pregnancy outcomes of embryo transfer with D2 or D3 embryos in patients with poor ovarian response.
Methods: The pregnancy outcomes of 620 patients who had poor ovarian response and underwent the first in vitro fertilization-embryo transfer (IVF-ET) were retrospectively analyzed. Of the 620 cycles, all available fresh D2 embryos were used in 365 cycles (day 2 embryo transfer) and all available fresh D3 embryos were used in 255 cycles (day 3 embryo transfer) without superfluous embryos for freezing.
Results: There was a significant difference in clinical pregnancy rate between day 2 (32.73 %) and day 3 (50.83 %) embryo transfer in younger than 35-year-old patients, but no significant differences in implantation rate, live birth rate and spontaneous abortion rate (P > 0.05). There were similar pregnancy outcomes between day 2 and 3 embryo transfer in 35-year and older patients.
Conclusion: D3 embryo transfer may have better pregnancy outcomes in younger than 35-year-old patients with poor ovarian response.