What should we focus on before preimplantation genetic diagnosis/screening?

Introduction: Preimplantation genetic diagnosis/screening (PGD/PGS) can effectively detect chromosomal abnormalities in an embryo but only if an embryo is available. However, not all couples can obtain an embryo that is available for testing. The purpose of this study was to identify factors which might affect the formation of PGD/PGS embryos to predict the possibility of obtaining embryos that could be detected.

Material and methods: In a retrospective study, we included all couples who underwent PGD/PGS at our center from January 2015 to December 2016. We compared these patients according to the non-blastocyst group and the blastocyst group.

Results: There were 302 couples who had blastocysts in their first PGD/PGS cycle. Fifty-seven couples had no blastocysts in their PGD/PGS cycles: 43 couples had no blastocysts in one cycle; 10 in two cycles; 4 in three cycles. The non-blastocyst group was older than the blastocyst group (32.37 vs. 30.69, p = 0.048). Anti-mullerian hormone (AMH, ng/ml) in the non-blastocyst group was significantly lower than in the blastocyst group (4.80 ±3.67 vs. 3.07 ±2.30, p = 0.00). Women whose chromosome were aneuploid (47, XXX or 45, X) had a similar AMH level compared with others, but the number of retrieved oocytes was much lower; the normal karyotype was 14.25 and aneuploidy was 5.40 (p = 0.01) in women < 30 years old. There was the same condition in women aged 30-38 years (14.60 vs. 3.44, p < 0.001). Male's different chromosome karyotype had no influence on double pronuclear number or the rate of blastocyst formation. Presence of endometriosis, polycystic ovary syndrome and tubal factor showed no difference between the blastocyst and non-blastocyst group. Nor did oligospermia and asthenospermia.

Conclusions: Elderly women, those with lower AMH and women with 47, XXX or 45, X have fewer ova, leading to the possibility of no blastocyst. These couples should be fully informed and weigh the advantages and disadvantages before undergoing PGD/PGS.