Evaluating PGT-A in patients with limited good-quality embryos: A retrospective cohort study

Background: Preimplantation genetic testing for aneuploidy (PGT-A) is widely used to screen for aneuploidy with the aim of improving the live birth rate. Remarkably, previous studies have focused on the effect of PGT-A on cumulative clinical outcomes in women with a good pregnancy prognosis. However, it is still unclear whether PGT-A is superior for cumulative pregnancy outcomes in patients with limited good-quality embryos. Methods: In total, 1553 patients who intended to pursue PGT-A for the first time but only obtained two or fewer good-quality embryos on day 3 after oocyte retrieval were divided into two groups: 997 in the PGT-A group and 556 in the drop-out group (i.e., decided not to undergo PGT-A due to poor embryological outcome). The main outcome measures were cumulative live birth rate per oocyte retrieval cycle and live birth rate per embryo transfer (ET) cycle. Results: After adjustment for potential confounders, the PGT-A group exhibited significantly lower cumulative rates of biochemical pregnancy [19.96 % vs. 30.22 %, p-adjusted (p-adj) < 0.001], clinical pregnancy (17.55 % vs. 23.38 %, p-adj < 0.001) and live birth (14.14 % vs. 16.19 %, p-adj = 0.005) per oocyte retrieval compared with the drop-out group. In contrast, when analysed per ET procedure, the PGT-A group showed marked improvements in rates of biochemical pregnancy (72.16 % vs. 35.50 %, p-adj < 0.001), clinical pregnancy (61.86 % vs. 26.98 %, p-adj < 0.001) and live birth (48.45 % vs. 18.26 %, p-adj < 0.001) compared with the drop-out group. No significant differences were observed in cumulative miscarriage and ectopic pregnancy rates, number of ETs per live birth, and neonatal outcomes between the groups. Conclusions: This retrospective study of patients with limited good-quality embryos found that the PGT-A group had a lower cumulative live birth rate per oocyte retrieval, but superior pregnancy outcomes per ET compared with the drop-out group.