Objectives: To evaluate whether the use of Pre-implantation Genetic Screening (PGS) significantly improve the clinical outcome for IVF patients following FET cycles at Alpha Fertility Centre, Malaysia.

Methods: Seven-hundred-and-eighty-six (786) patients who had vitrified-warmed blastocysts transferred from July 2013 to December 2016 were analysed. In the non-PGS-group, blastocysts were vitrified without biopsy. In the PGS-group, 2-8 trophectoderm cells were biopsied before the blastocysts were vitrified. PGS was performed using either Micro-array Comparative Genomic Hybridisation (MaCGH) or Next Generation Sequencing (NGS). All blastocysts were vitrified on day 5 and/or day 6; and warmed using the Cryotec method (Cryotech, Japan) for elective FET. The cases were stratified into 5 age groups: <35, 35-37, 38-40, 41-42 and >42. In each age group, number of cases in non-PGS-group and PGS-group were 258 vs 231, 68 vs 67, 60 vs 61, 20 vs 13 and 4 vs 4 respectively. A total of 683 unscreened blastocysts and 487 euploid blastocysts were warmed and transferred in non-PGS-group and PGS-group respectively. All 1170 blastocysts survived post-thaw with morphologically intact inner cell mass and trophectoderm cells (100% post-thaw survival rate). All 1170 blastocysts that had been thawed were transferred.  Clinical pregnancy and number of gestational sacs (IUGS) were determined using ultrasound.

Results: The mean age of patients in each group was similar (p>0.05): non-PGS-group was 32.2 (range 18-44) and PGS-group was 32.2 (range 18-43). The mean number of blastocysts transferred was 1.7 and 1.3 for non-PGS-group and PGS-group respectively (p<0.0001). CPR for PGS-group was significantly higher than non-PGS-group (66.2% vs 55.9%; p=0.0034), particularly in age group 35-37 (71.6% vs 54.4%; p=0.0499) and 41-42 (69.2% vs 20.0%; p=0.0096). Correspondingly, implantation rate (IR) for PGS-group was also significantly higher than non-PGS group (60.2% vs 46.9%; p=0.0001). IR was statistically significant for all age groups more than 34 years old: 35-37(66.7% vs 44.9%; p=0.0032), 38-40(54.1% vs 32.6%; p=0.0069), 41-42(71.4% vs 14.7%; p=0.0003) and >42(75.0% vs 0.0%, p=0.0242). (30.7% vs 55.0%, p=0.0001). 

Conclusion: PGS significantly increases the IR compared with non-PGS cases in frozen blastocyst transfer. PGS also significantly increases the CPR compared with non-PGS cases in frozen blastocyst transfer even with a lower mean number of blastocysts transferred (1.3 vs 1.7).