Optimal euploid embryo transfer strategy, fresh versus frozen, after preimplantation genetic screening with next generation sequencing: a randomized controlled trial

Fertil Steril. 2017 Mar;107(3):723-730.e3. doi: 10.1016/j.fertnstert.2016.12.022. Epub 2017 Jan 27.


Objective: To compare two commonly used protocols (fresh vs. vitrified) used to transfer euploid blastocysts after IVF with preimplantation genetic screening.

Design: Randomized controlled trial.

Setting: Private assisted reproduction center.

Patient(s): A total of 179 patients undergoing IVF treatment using preimplantation genetic screening.

Intervention(s): Patients were randomized at the time of hCG administration to either a freeze-all cycle or a fresh day 6 ET during the stimulated cycle.

Main outcome measure(s): Implantation rates (sac/embryo transferred), ongoing pregnancy rates (PRs) (beyond 8 weeks), and live birth rate per ET in the primary transfer cycle.

Result(s): Implantation rate per embryo transferred showed an improvement in the frozen group compared with the fresh group, but not significantly (75% vs. 67%). The ongoing PR (80% vs. 61%) and live birth rates (77% vs. 59%) were significantly higher in the frozen group compared with the fresh group.

Conclusion(s): Either treatment protocol investigated in the present study can be a reasonable option for patients. Freezing all embryos allows for inclusion of all blastocysts in the cohort of embryos available for transfer, which also results in a higher proportion of patients reaching ET. These findings suggest a trend toward favoring the freeze-all option as a preferred transfer strategy when using known euploid embryos.

Clinical trial registration number: NCT02000349.

Keywords: PGS; aneuploidy; embryos; transfer.

Publication types

  • Comparative Study
  • Randomized Controlled Trial

MeSH terms

  • Adult
  • Biopsy
  • Blastocyst / physiology*
  • Cryopreservation*
  • Embryo Culture Techniques
  • Embryo Implantation
  • Embryo Transfer* / adverse effects
  • Female
  • Fertility
  • Fertilization in Vitro* / adverse effects
  • Genetic Testing*
  • High-Throughput Nucleotide Sequencing*
  • Humans
  • Infertility / diagnosis
  • Infertility / physiopathology
  • Infertility / therapy*
  • Live Birth
  • Oregon
  • Ploidies*
  • Predictive Value of Tests
  • Pregnancy
  • Pregnancy Rate
  • Preimplantation Diagnosis / methods*
  • Risk Factors
  • Treatment Outcome
  • Vitrification

Associated data

  • ClinicalTrials.gov/NCT02000349