Assessing the Impact of Comprehensive Chromosome Screening in Preimplantation Genetic Testing for Aneuploidy: A Meta-Analytical Review

Biotechnology

The utility of pre-implantation genetic testing (PGT-A) is controversial, with older meta-analyses demonstrating improved pregnancy outcomes, while newer trials have not shown benefit. Therefore, we performed a meta-analysis which aimed to evaluate the benefits of PGT-A using comprehensive chromosome screening (CCS) and its effects on in vitro fertilization (IVF) outcomes among randomized controlled trials (RCTs). We conducted a systematic search to identify RCTs comparing women undergoing PGT-A with CSS with women not undergoing PGT-A, from inception to December 2020. Random effects meta-analysis was utilized to calculate average odds ratios (OR) for clinical pregnancy rate (CPR), ongoing pregnancy rate (OPR), and miscarriage rate (MR). The heterogeneity of exposure was assessed using Forest plots and I2 statistics. Publication bias was evaluated using Egger’s test. Among 1251 citations, seven RCTs met the inclusion criteria. Biopsies of embryos were carried out at various developmental stages, including polar body, day 3, and day 5-6 of culture. Data was analyzed as all studies and blastocyst only. Meta-analysis failed to show improvement in OPRs using PGT-A in the all ages, <35 years old and ≥ 35 years old age groups. There was also no significant difference in CPRs in any group. The MR decreased with the use of PGT-A (among all biopsy types and among blastocyst biopsies) in the all-ages group, but not when stratifying according to patient age, <35 and ≥ 35 years old. More data regarding the risks and advantages of PGT-A are needed to make a final decision on the value of this intervention in clinical practice. The exact magnitude of the benefit of PGT-A selection cannot be correctly determined until multiple standardized protocol IVF PGT-A trials are conducted.

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