Assosiation Between High Gonadotropin Dosage, Euploidyand Pregnancy Rates In Pgt Cycles.

Preimplantation genetic testing (PGT) has been proven to be the most effective and reliable method for embryo selection in IVF cycles [1, 2]. Euploidy and blastulation rates decrease significantly with advancing maternal age [3, 4]. At the same time, in order to recruit an adequate number of follicles the average dosage of gonadotropins administered during controlled ovarian stimulation in IVF cycles increases significantly with advancing maternal age. The objective of this study was to evaluate the association between the euploidy rates and pregnancy rates, and total dosage of gonadotropins administered in matched age groups in IVF PGT cycles. A retrospective study of SNP PGT outcome data from blastocysts biopsied on day 5 or day 6 was conducted to identify differences in euploidy and clinical pregnancy rates. 479 cycles of IVF treatment with PGT between January 2013 and February 2016 followed by 497 frozen embryo transfers were included in the study (351 patients, maternal age - 37.6±4.1). A total of 2610 embryos were analyzed by SPN PGT (5.45±2.6 per case) for euploidy rates. All embryos were vitrified after biopsy, and selected embryos were subsequently thawed for a hormone replacement frozen embryo transfer cycle. All cycles were divided in three groups by total gonadotropin dosage (<3000 IUs, 3000-5000 IUs, and > 5000 IUs), in four groups by number of eggs retrieved (1-5, 5-10, 10-15, and >15 eggs) and in four age groups (<35, 35-37, 38-40, and ≥41 y.o.). Clinical pregnancy rate was defined by the presence of a fetal heartbeat at 6-7 weeks of pregnancy. Euploidy rates within the same age group were not statistically different regardless of the total dosage of gonadotropins used or the number of eggs retrieved in IVF PGT cycles. In a group of young patients (<35 y.o. - 101 patients) euploidy rates ranged from 61.03% to 66.67%, when analyzed by total dosage of gonadotropins used in the IVF cycle and from 59.82% to 67.12%, when assessed by the total number of eggs retrieved, χ2= 0.3059, p=0.5802. Similar data were obtained in a group of older patients (≥41 y.o - 137 patients): euploidy rates ranged from 25.78% to 32.86% when analyzed by total dosage of gonadotropins used in the IVF cycle and from 29.47% to 46.15%, when assessed by the total number of eggs retrieved, χ2= 1.117, p=0.02906. Ongoing pregnancy rates were similar, not only within particular age groups, but also between different age groups regardless of the total dosage of gonadotropins used or the number of eggs retrieved: ranging from 56.57% to 68.18% (p=0.3642, χ2=0.6357). High gonadotropin dosage does not affect euploidy and pregnancy rates in IVF PGT cycles. Euploidy rates are defined primarily by patient age regardless of the number of eggs retrieved.