ESHRE study

At its 26th Annual Meeting in Rome the European Society of Human Reproduction and Embryology (ESHRE) PGS Task Force presented the results of its proof of principle study into PGS screening by polar body biopsy.

Results of this study confirm polar body screening is a reliable method to analyse the chromosomal status of an egg.

Scientists at the University of Bonn and at the SISMER centre in Bologna used 24sure to screen all chromosomes in one cell within 12 hours, allowing for fresh transfer of the egg. The chromosomal status of the eggs in 89 % of all polar bodies was correctly identified.

The researchers biopsied both polar bodies, one and two, from a total of 226 zygotes (fertilised eggs) from 42 cycles in 41 couples with an average maternal age of 40 years. In 19 cycles all zygotes were aneuploid, leading to a transfer of only 37 embryos in 23 cycles. 10 of these embryos implanted and resulted in 8 clinical pregnancies  – a 27 % implantation rate per embryo transfer.

Of the 177 analysed eggs, 34 were euploid and 122 aneuploid. The results showed that in 140 combinations of polar bodies and eggs that were analysed 125 (89 %) polar body analyses confirmed the chromosomal status of the eggs and 15 (11 %) did not. The reason for the non-concordance of the 15 eggs was not discussed.

In both centres all eggs from patients that were obtained after ovarian hyperstimulation, egg retrieval and fertilisation were biopsied for polar bodies 1 and 2. In those cases where aneuploidy  was predicted, the egg was studied with 24sure to confirm the findings. The Centre for Reproductive Medicine in Amsterdam analysed all data and provided the final results.

The analysis of polar body 1 already detected 72 % of all aneuploid eggs, but adding the analysis of the second polar body significantly improved the detection rate up to 89 %.