Positive outcome after preimplantation diagnosis of aneuploidy in human embryos *

Abstract

usromosomal abnormalities are responsible for a great deal of embryo wastage, which is reflected, at least partially, in decreased implantation and increased miscarriage in older women. To address this problem the transfer of only chromosomally normal embryos previously selected by preimplantation genetic diagnosis (PGD) has been proposed. We designed a multi-centre in-vitro fertilization (IVF) study to compare controls and a test group that underwent embryo biopsy and PGD for aneuploidy. Patients were matched retrospectively, but blindly, for average maternal age, number of previous IVF cycles, duration of stimulation, oestradiol concentrations on day +1, and average mature follicles. All these parameters were similar in test and control groups. Only embryos classified as normal for those chromosomes were transferred after PGD. The results showed that the rates of fetal heart beat (FHB)/embryo transferred between the control and test groups were similar. However, spontaneous abortions, measured as FHB aborted/FHB detected, decreased after PGD (P < 0.05), and ongoing pregnancies and delivered babies increased (P < 0.05) in the PGD group of patients. Two conclusions were obtained: (i) PGD of aneuploidy reduced embryo loss after implantation; (ii) implantation rates were not significantly improved, but the proportion of ongoing and delivered babies was increased.

Advances and Controversies in Assisted Reproductive Technology

“…Many investigators have attempted to achieve this goal, but to date, these studies either have design flaws or have been contradictory in their results. 51,52,54,55 A recent meta-analysis by Twisk et al, 56 which included 2 randomized controlled trials, did not find a statistically significant difference in the clinical pregnancy rate (15% in PGS versus 20% in controls) or live birth rate (11% in PGS versus 15% in controls). Mastenbroek et al 57 published in 2007 a large, multicenter, randomized, double-blinded trial demonstrating that PGS with a 1-cell biopsy using FISH analysis in women between 35 to 41 years not only did not improve but instead significantly reduced the ongoing pregnancy and live birth rates after IVF.…”

Genetic Considerations in Recurrent Pregnancy Loss

“…Because the chromosomal content of the blastomeres that were not sampled is inferred from the chromosomal content of the single cell that was, false positive and false negative results are frequent. Although removing a second blastomere at the time of sampling may improve accuracy, this comes at the cost of decreases in embryo survival (Harper et al 1995;Delhanty 1997;Munné et al 1999;De Vos et al 2009;Harton et al 2011). A significant disadvantage of cleavage stage blastomere biopsy is the associated decrease in implantation rates for biopsied embryos (Coco 2014).…”

Analysis of nine chromosome probes in first polar bodies and metaphase II oocytes for the detection of aneuploidies

“…In some studies up to nine different chromosomes are analysed 18 -20 and the success of ART is slightly improved. A reduction in abortions 19,20 and even an increase in implantation rate 20 has been observed, although the percentage of pregnancies has not increased. 21 Since, as reported, 90% of embryo aneuploidy is the result of nondisjunction in maternal meiosis I, 22 detection of abnormal oocytes through the analysis of their first polar body (1PB) in an in vitro fertilisation (IVF) treatment is an important goal.…”