Polar body biopsy and aneuploidy testing by simultaneous detection of six chromosomes

To simultaneously detect six chromosomes in a single round of fluorescence in situ hybridization (FISH) during polar body diagnosis and aneuploidy testing in human in vitro fertilization (IVF) treatment.

A commercially available five-color FISH probe was modified by an additional chromosome probe. This kit was first tested on lymphocyte spreads and then used for polar body diagnosis (PBD) in patients with advanced maternal age and repeated implantation failure. The outcome of IVF treatment was compared with a control group.

All six chromosomes could be simultaneously detected and easily distinguished by FISH analysis. PBD and aneuploidy testing were performed in 75 treatment cycles and compared with 126 controls. The biochemical pregnancy rate was significantly higher in the PBD group (37.1% vs 22.9%, p < 0.05) and a trend was observed for higher clinical pregnancy and implantation rates (24.22% and 14.4% vs 18.62% and 10.8%, respectively) and lower abortion rates (20% vs 31.8%) following PBD.

The simultaneous detection of six chromosomes in a single FISH round is possible and can be applied to PBD. This approach may present another step towards increasing the number of chromosomes for aneuploidy testing.