The correlation between the number of oocytes retrieved and PGT clinical outcomes: a population study of 1084 PGT cycles

Abstract Background PGT is widely used in IVF center to improve the clinical outcomes. The number of oocytes retrieved is a critical indicator in IVF-PGT cycle.Therefor, We aim to determine whether the number of retrieved oocytes can affect the clinical outcomes of patients who undergoPGT. Methods The participating patients were divided into 6 groups according to the number of oocytes retrieved. The clinical outcomes of patients who underwent PGT and euploid blastocyst transfer at our IVF centre between January 2017 and December 2022 were retrospectively analysed. Results A total of 1084 cycles were includedin our study. Patient age and AMH levels were positively correlated with the number of oocytes retrieved and were significantly different among the 6 groups (PP=0.200 and P=0.065, respectively). The MII oocyte rate, 2PN embryo rate, and blastocystrate were significantly different among the 6 groups (PP=0.257). The genetic testing revealedthat the euploid blastocyst rate and mosaic blastocyst rate were significantly different among the 6 groups (P=0.014 and P=0.038, respectively). The number of OHSS patients did not significantly differ among the 6 groups (P=0.110). After FET, the implantation rate (P=0.057), ectopicpregnancy rate (P=0.496), miscarriage rate (P=0.986), pretermbirth rate (P=0.051), birth defectrate (P=0.544), neonatal weight (P=0.913) and livebirth rate (P=0.339) did not significantly differ among the6 groups. Both the clinicalpregnancy rate and cumulative live birth rate were significantly different among the 6 groups(P=0.046 and PConclusion Our results suggest that the clinical pregnancy rate and cumulativelive birth rate of 21-25 oocytes increase, after which they plateau and donot increase therisk of OHSS. Thus, 21-25 is theoptimal number of oocytes retrieved in PGT cycles.