IFFS/JSRM International Meeting 2015(2015.4.26-29 Yokohama）

Comparison of the clinical outcomes between fresh embryo transfers and frozen-thawed blastocyst transfers over the last decade.

• Objective

  To compare the clinical outcomes between fresh embryo transfers (ET) and frozen-thawed blastocyst transfers (FET) for decade years and evaluate the impact of cryopreservation to neonates.

• Materials and Methods

  We retrospectively reviewed 5561 ET cycles and 3137 FET cycles from January 2002 to December 2013. Outcome measures include the clinical pregnancy rate, delivery rate, multi pregnancy rate, sex ratio, mean birth weight, mean gestational age and malformation rate of the neonates.

• Results

  No differences were observed in the average of clinical pregnancy, delivery rate and multi pregnancy rate between ET and FET (15.5%, 68.3%, 11.1% vs. 28.5%, 70.2%, 14.4%). The number of FET per the number of total transfer cycles per year has increased from 2002 to 2013 from 20.5% to 45.5%. The contribution of FET to the number of clinical pregnancy and delivery has also increased (from 25.5% to 60.5%, from 26.6% to 60.3%). The sex ratio, mean birth weight and mean gestational age did not differ significantly between ET and FET (1.10, 2943.2±494.8g, 38.7±2.09W vs. 1.37, 3028.4±474.0g, 38.9±2.14W). However, the malformation rate of FET was significant higher than ET (3.36% vs. 1.30%, p<0.05).

• Conclusions

  It was found that FET contribute to IVF success rates for decade years. There was no significant impact on the neonates by cryopreservation, but the malformation rate of FET was significantly higher than ET. Further studies are needed to evaluate the impact of cryopreservation to neonates.