Frozen embryo transfer after PGT-A cycles: To wait or not to wait?

Abstract

Objective

The aim of the study is to assess whether delaying frozen embryo transfer (FET) after pre-implantation genetic testing for aneuploidy (PGT-A) cycle provides any benefit for reproductive outcomes.

Methods

Retrospective cohort study including a total of 913 frozen embryo transfers related to 5104 PGT-A cycles performed between May 2016 and March 2017 at IVI clinics. We compared the FET performed the month following the ovarian puncture (OPU) (n = 184) with the FET delayed one or more months (n = 700). The main outcome was clinical pregnancy rate (CPR) and the secondary outcomes were implantation (IR) and miscarriage rates.

Results

No significant statistical differences were detected between groups as regards patient age and cycle parameters. Similar results were also observed concerning metaphase II oocytes (11 ± 0.8 vs 10 ± 0.4, p = 0.03), number of blastocysts (4.3 ± 0.4 vs 3.8 ± 0.2, p = 0.122), euploid embryos (2.1 ± 0.3 vs 1.8 ± 0.1, p = 0.039), or transferred embryos (1.1 ± 0.1 vs 1.1 ± 0.2, p = 0.52). Finally, no significant differences were found in CPR (52.7% vs 54.9%, p = 0.33). The multivariate logistic regression showed that the number of euploid (OR = 1.170, 1.062–1.288; p = 0.001) and transferred embryos (OR = 2.530, 1.703–1.509; P< .001) significantly affected the probability of getting pregnant, while the timing of the frozen embryo transfer (OR = 1.090, 0.787–1.509; p = 0.604) did not have a significant effect on reproductive outcomes.

Conclusions

Delaying frozen embryo transfer after PGT-A cycles does not seem to improve outcomes in terms of pregnancy rates.