P-557 The contribution of PGT-A to PGT-M and PGT-SR clinical outcomes – A single centre retrospective analysis
Authors: Campbell-Forde M , Drew E , Odia R , Cawood S , Douglas K , Seshadri V , Theodorou S , Carroll M , Serhal P 
Published: July 2024

Abstract

Study question
To determine if the introduction of concurrent testing with PGT-A has improved clinical outcomes for PGT-M/SR patients.

Summary answer
This study demonstrates that the introduction of concurrent testing may have improved clinical outcomes for this patient demographic irrespective of age.

What is known already
Preimplantation Genetic Testing (PGT) is utilised to investigate the genetic constitution of embryos. PGT-M (monogenic) and PGT-SR (structural rearrangements) are screening techniques considered in treatment for couples at risk of conceiving offspring with known genetic or structural chromosomal abnormalities respectively. Preimplantation Genetic testing for Aneuploidy (PGT-A) was developed in order to screen embryos for numerical chromosomal abnormalities, a leading cause of failed implantation. Nevertheless, routine use of PGT-A is discouraged due to lack of evidence regarding its efficacy. However, PGT-A is routinely used alongside PGT-M and PGT-SR despite the lack of evidence of its effectiveness in improving patient outcomes.

Study design, size, duration
The retrospective analysis of 496 PGT-M/SR single embryo transfer patient cycles between December 2013 and December 2021.

Participants/materials, setting, methods
The retrospective analysis of 496 PGT-M/SR single embryo transfer cycles at CRGH Portland was undertaken (single testing n = 77; concurrent testing n = 419). The clinical outcomes (positive urine pregnancy test, clinical pregnancy, live birth and miscarriage rates) were compared between groups using IBM SPSS Statistics (premium 27). Binary logistic regression was performed for statistical analysis, results with p &lt; 0.05 were determined statistically significant.

Main results and the role of chance
Overall, concurrent testing was associated with statistically significant improved clinical outcomes compared to the reference group. Statistical significance was seen in positive urine pregnancy test (49% vs 68%, p = 0.012), clinical pregnancy (32.5% vs 63%; p = 0.000013), live birth rate (32.5% vs 59%; p = &lt;0.00016) and miscarriage rates (34.2% vs 13%; p = 0.001). The results imply that the introduction of concurrent testing has improved the probability of obtaining a positive clinical outcome and has reduced the chance of miscarriage in this patient demographic. Further analysis showed concurrent testing improved the chances of obtaining a positive clinical outcome irrespective of the patients age or quality of the embryo.

Limitations, reasons for caution
This study has produced promising results. However, there are several limitations such as the small sample size, embryo biopsy techniques used, and the different molecular diagnostic techniques and providers utilised.

Wider implications of the findings
The results imply a justification for the use of PGT-A alongside PGT-M/SR screening techniques to improve embryo selection and clinical outcomes for this cohort of patients. Additionally, they demonstrate the efficacy of PGT-A in a previously underrepresented demographic. However, further research is required to confirm the clinical value of PGT-A.

Trial registration number
not applicable