Multiple cryopreservation-warming cycles, coupled with blastocyst biopsy, negatively affect IVF outcomes

Research question: Do multiple cryopreservation-warming cycles, coupled with blastocyst biopsy, negatively affect IVF outcomes? Design: Patients undergoing IVF with homologous single embryo transfer, and who underwent trophectoderm biopsy for preimplantation genetic testing for aneuploidy (PGT-A) between 2013 and 2017, were divided into three groups based on degree of embryonic micromanipulation: once-biopsied, once-cryopreserved (group BC, n = 2603), oncebiopsied, twice-cryopreserved (group CBC, n = 95) and twice-biopsied, twice-cryopreserved (group BCBC, n = 15). The primary outcome was live birth; secondary outcomes included positive serum pregnancy test, clinical pregnancy and miscarriage. Results: Group CBC had a significantly lower chance of live birth (adjusted RR 0.57, 95% CI 0.41 to 0.79) and clinical pregnancy (adjusted RR 0.67, 95% CI 0.53 to 0.85) compared with group BC. Miscarriage rates were similar between groups BC and CBC (adjusted RR 1.3, 95% CI 0.64 to 2.7). Conclusions: Multiple cryopreservation-warming cycles, coupled with blastocyst biopsy, negatively affect IVF outcomes. Although PGT-A is thought to improve reproductive outcomes on a per transfer basis, caution must be exercised in counselling patients on the possibility of diminishing returns owing to further embryonic micromanipulation after an embryo has been cryopreserved.

Automated summary

The study demonstrates that multiple cryopreservation-warming cycles, coupled with blastocyst biopsy, have a negative impact on IVF outcomes, including reduced live birth and clinical pregnancy rates. However, there was no significant difference in miscarriage rates between the groups. Therefore, caution should be exercised when considering further embryonic micromanipulation after cryopreservation.