PGS and PGD as efficient tools to select embryos with a higher implantation potential in advanced maternal age patients

Abstract

OBJECTIVE: Preimplantation genetic diagnosis (PGD) and preimplantation genetic aneuploidy screening (PGS) techniques are important tools to select embryos that are free from certain genetic disorders. The aim of this study was to evaluate the efficiency of PGD and PGS in patients from different age groups. DESIGN: Retrospective. MATERIALS AND METHODS: A longitudinal observation study was performed comparing two groups of patients: G1, where 192 patients were subjected to PGD or PGS and G2, where 986 patients were included as a control group. The inclusion criteria for patients in G1 were: implantation failure, previous miscarriages due to fetal chromosomal abnormalities, >3 good morphology embryos available for biopsy, history of inherited genetic disease and X linked disorders. A total of 879 and 4579 embryos were obtained in G1 and G2, respectively. PGD and PGS were performed by fluorescence in-situ hybridization (FISH). The chromosomes that were analyzed were as follows: X, Y, 13, 16, 18, 21 and/or 22, depending on the indication. Statistical analyses were performed using the Chi-square test and one-Way ANOVA with significance at P<0.05. RESULTS: Mean age of female patients in G1 and G2 was 37.4 ± 5.73 and 34.1 ± 4.57 years, respectively. The clinical pregnancy rate was not statistically different in G1 (49.0%) when compared to the control group (56.3%). In G1 66.1% of the patients and 40.3% in G2 were >35 years. The implantation and pregnancy rates of patients (>35 years) were similar in both groups (12.7% and 32.8% vs. 12.1% and 33.2%) in G1 and G2, respectively. In the PGS group, the pregnancy and the miscarriage rates (42.9% and 13.3%) registered in patients >35 years were better than the observed in the same age group from G2 (33.2% vs. 35.8%). The best results were observed in PGS patients >40 years with higher pregnancy rate and lower miscarriage rate (45% and 20%) when compared with G2 >40 years group (26% and 61%). CONCLUSIONS: The increased pregnancy and implantation rates and a lower miscarriage rate were observed when using PGD and PGS for euploid embryo selection prior to transfer, particularly in the advanced maternal age group. Our findings suggest that patients older than 35 years could benefit from the use of PGS in order to select embryos with a higher implantation potential.