P-253 Clinical efficacy of PGT-A according to maternal age and embryo quality in blastocyst stage
Authors: Laguna Rodriguez T , Serrano Molina M , Romero Olmedo M D L S , De Andrés Cara M , Rico Nieto E , Fernández González M J , Pomares Toro E 
Published: June 2023

Abstract

Study question
To establish the usefulness of PGT-A as an embryo selection tool based on the quality of the blastocyst and the age of the patient.

Summary answer
The euploidy rate of good quality blastocysts decreases dramatically with increasing maternal age.

What is known already
One of the fundamental objectives to achieve an optimal gestation rate is the selection of the embryo with the highest implantation potential. For this purpose, morphokinetics and aneuploidy detection are used. Most aneuploidies arise in maternal meiosis, and increase exponentially in women over the age of 35 years, coinciding with the rapid decline in IVF success and live birth rates in patients of advanced maternal age.

Study design, size, duration
In the present retrospective study, embryo quality of 321 blastocysts was evaluated from June 2020 to January 2023. They were analyzed according to the ASEBIR (2015) classification and using preimplantation genetic testing for aneuploidy (PGT-A) with next-generation sequencing (NGS).

Participants/materials, setting, methods
A total of 321 blastocysts were analyzed using PGT-A from which 101 were euploid. This 101 blastocysts were classified according to the morphokinetic (A or B (good quality) and C (medium quality)) and the maternal age (&lt;35, 35-36, 37-38, 39-40, 41-42, 43-44 and 45 -46 years). Out of the 101 euploid blastocysts, 78 embryos were classified as A or B (good quality) and 23 as C (medium quality) according to the ASEBIR classification.

Main results and the role of chance
The euploidy rate of the embryos decreases as the age of the patient increases, being 73% for good quality embryos in patients under 35, 54% in patients between 35-36, 37% in patients between 37- 38, 31% in patients between 39-40, 23% in patients between 41-42, 5% in patients between 43- 44 and 0 % in patients between 45-46 years. For medium quality embryos, the euploidy rate is 58% in patients under 35, 38% in patients between 35-36, 30% in patients between 37-38, 26% in patients between 39-40, 0% in patients between 41-42, 0% in patients between 43-44 and 0% in patients between 45- 46 years.
In patients under 35 years, PGT-A will improve pregnancy rates considering that it is an invasive and costly technique. In patients between 35-36 years, PGT-A is a very useful tool when embryos have C quality as well as, in patients between 37- 40, regardless of embryo quality. Furthermore, patients between 41-42 years with good quality embryos, PGT-A will decrease the abortion rates and increase the pregnancy rates. In contrast, patients with C-quality embryos should not start new cycles, as well as patients with over than 43 years due to the low probability of euploidy.

Limitations, reasons for caution
Studies of larger sample size and study period are required to validate our current findings. Furthermore, more information about fertilization, pregnancy, birth rate and perinatal outcomes could improve the current results.

Wider implications of the findings
Making the decision whether or not to use PGT-A on the day of blastocyst formation helps to choose the best strategy by individualizing each case according to the maternal age and the quality of the blastocysts. Decreasing cycle times will always be beneficial to patients and their outcomes.

Trial registration number
Does not apply