Objectives

To evaluate the effects of vitrification and embryo development on implantation rate, clinical and ongoing pregnancy rates along with live birth rate.

Methods

•  A randomized, retrospective study
•  Fresh and vitrified-warmed blastocyst transfer (BT)
•  Statistical methods: Student t test and Yate’s continuity corrected χ-square
•  Definition:

1. Biochemical pregnancy: blood β-hCG > 5mIU/mL
2. Clinical pregnancy: gestational sac observed under ultrasound at 6-8 weeks of pregnancy
3. Ongoing pregnancy: pregnant after 5 months
4. Implantation rate: gestational sac or fetal heart beat (FHB) per transferred embryo

Conclusions

Our preliminary data suggested that:

1.          Vitrification had no obvious adverse effect on embryos. In fact, it could be beneficial to increase cumulative pregnancy rate.

2.          The implantation rate and pregnancy rate after D6 BT were both lower than D5 BT, implying the importance of embryo growth rate.