To test or not to test? A framework for counselling patients on preimplantation genetic testing for aneuploidy (PGT-A).

Murphy LA1,2, Seidler EA1,2, Vaughan DA1,2, Resetkova N1,2, Penzias AS1,2, Toth TL1,2, Thornton KL1,2, Sakkas D1.

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Abstract

STUDY QUESTION:

What is the treatment path and cumulative live birth (CLB) rate from a single oocyte retrieval of patients who intend to pursue PGT-A at the start of an IVF cycle compared to matched controls?

SUMMARY ANSWER:

The choice of PGT-A at the start of the first IVF cycle decreases the CLB per oocyte retrieval for patients <38 years of age, however patients ≥38 years of age benefit significantly per embryo transfer (ET) when live birth (LB) is evaluated.

WHAT IS KNOWN ALREADY:

PGT-A has been shown to reduce the practice of transferring multiple embryos and to confer a higher live birth rate per transfer.

STUDY DESIGN, SIZE, DURATION:

This is a retrospective cohort study from December 2014 to September 2016, involving 600 patients: those intending PGT-A for their first IVF cycle (N = 300) and their matched controls. Post-hoc power calculations (alpha of 0.05, power of 0.80) indicated that our study was powered adequately to demonstrate significant differences in CLB per retrieval and LB per transfer.

PARTICIPANTS/MATERIALS, SETTING, METHODS:

The study was performed at a large academically affiliated infertility practice where approximately 80% of patients have insurance coverage for fertility care. Patients were identified through electronic medical records, and those who intended to pursue PGT-A at the start of stimulation were assessed. Patients were matched by age, time of oocyte retrieval and oocyte yield to the same number of controls. CLB outcomes per single retrieval, including the fresh and frozen transfers arising from the initial stimulation cycle, were calculated.

MAIN RESULTS AND THE ROLE OF CHANCE:

PGT-A was not beneficial when CLB rate was assessed per retrieval, however its benefits were significant when LB rate was assessed per transfer. First cycle, <38 year-old patients who intended to have PGT-A had a significantly (P < 0.001) lower CLB rate per oocyte retrieval compared to controls (49.4% vs. 69.1%). Conversely, patients ≥ 38 years in the PGT-A group had similar CLB rates compared to controls per oocyte retrieval, while LB rates per transfer were doubled compared to controls (62.1% vs. 31.7%; P < 0.001). Of the first-cycle PGT-A and control patients, 25.3% and 2.3% failed to achieve a transfer, respectively.

LIMITATIONS, REASONS FOR CAUTION:

This is not a true intention-to-treat study, due to its retrospective nature. Additionally, the number of patients with two or more previous miscarriages was significantly greater in the PGT-A group as compared to controls, however a sub-analysis showed that this failed to impact outcomes.

WIDER IMPLICATIONS OF THE FINDINGS:

The findings indicate that PGT-A may be detrimental for those <38 years old undergoing their first IVF cycle. PGT-A has the greatest clinical impact when a transfer is achieved in the ≥38 years old population. This study evaluates the typical treatment path following a patient's choice to pursue PGT-A at the cycle start, and can be used as a guide for counselling patients in relation to age and cycle number.