Correlation of Blastocyst Quality and Pregnancy Outcome during Freeze - Thaw Cycle

To explore the relationship between the blastocyst quality and biochemical pregnancy or early embryonic cessation of development during the freeze-thaw cycle of in vitro fertilisation embryo transfer (IVF-ET).

Descriptive study.

Reproductive Centre of Baoding Maternal and Child Health Hospital, from January 2014 to August 2019.

Eight hundred and twenty-nine embryos, treated by frozen-thawed blastocyst transfer, were analysed, retrospectively. These included 232 embryos in inner cell mass (ICM) Grade C, 272 embryos with trophoderm (TE) Grade C, and 325 embryos with Grades excluding C; ICM Grade and TE Grade were A or B. The pregnancy rate, rate of early embryonic cessation of development, and biochemical pregnancy rate were compared among the three groups after transfer.

Compared with embryos with Grades excluding C in the score (with 55.7% in clinical pregnancy rate, 6.5% in biochemical pregnancy rate, and 5.2% in early embryonic development arrest rate), the embryos with ICM Grade C has lower clinical pregnancy rate (43.5%), higher biochemical pregnancy rate (15.1%), and rate of early embryonic cessation of development (19.8%), while the embryos with TE Grade C has lower pregnancy rate (41.2%) and higher biochemical pregnancy rate (14.3%). The differences were statistically significant (all p ＜0.05). There was no significant difference about the above indicators between the ICM Grade C and TE Grade C groups (p >0.05).

Embryos with Grades excluding C in the score had better developmental potential and better prognosis. The rate of early embryonic development arrest in the ICM Grade C group was higher than that in the TE Grade C group. Key Words: Embryo quality and score, Blastocyst, Biochemical pregnancy, Early embryonic cessation of development.