Survival of cryopreservation and thawing with all blastomeres intact identifies multicell embryos with superior frozen embryo transfer outcome.

Objective: To assess the impact of survival of cryopreservation and thawing with all blastomeres intact on the outcome of multicell frozen ET.

Design: Retrospective study.

Setting: Academic assisted reproductive technology program.

Patient(s): One hundred sixteen exclusively multicell frozen ETs in 78 patients.

Intervention(s): Frozen ET.

Main Outcome Measure(s): Relation of embryonic blastomere survival to the outcome of frozen ET (i.e., pregnancy).

Result(s): When at least one embryo survived with all blastomeres intact, the total pregnancy rate (biochemical, clinical, or delivered) was 37.7%, the clinical pregnancy rate was 24.6%, and the delivered pregnancy rate was 18.8%. When no embryo survived with all blastomeres intact, the corresponding rates were 10.6%, 8.5%, and 6.4%. The differences in the total pregnancy rate and the clinical pregnancy rate were statistically significant. The delivered pregnancy rates approached statistical significance.

Conclusion(s): Multicell embryonic survival of cryopreservation and thawing with all blastomeres intact identifies embryos with superior developmental potential.