Lausanne, Switzerland: If a woman undergoing artificial reproductive techniques suffers repeated failures of embryos to implant in her uterus it may be because she has a chromosomal abnormality, according to new findings by Israeli fertility experts.
A team from the Assaf Harofeh Medical Centre in Tel Aviv carried out genetic screening on 65 couples who had experienced repeated embryo implantation failure and found that a quarter of the women and the husbands of two of them had abnormal chromosomes.
The study, led by Professor Raphael Ron-El, head of the centre's IVF unit, was too small to establish a causal link between chromosome abnormalities and repeated implantation failure, so the research team is calling for an international registry to be established for chromosomal aberrations in infertility patients.
Team member Dr Arieh Raziel told the European Society of Human Reproduction and Embryology meeting in Lausanne today (Wednesday 4 July) that they had gathered 16 cases of chromosomal changes in three years. "Even if an additional 15 IVF units joined the study, the numbers would still be too small to draw conclusions. So we need an international registry set up that will record infertility patients' chromosomal aberrations and their impact on pregnancy."
He said that women undergoing ART have a seven-fold higher prevalence of autosomal (non-sex chromosome) translocations than the general population, with over one in a hundred patients affected. The highest rate was found in women with recurrent miscarriages.
"If the causes for implantation failure after IVF are similar to the causes for recurrent miscarriages, but in an earlier phase, then chromosomal abnormalities could also be more frequent in implantation failure," he told the conference. The objective of the study was to find the type and frequency of chromosomal changes in implantation failure and evaluate their impact on the outcome of the pregnancies.
All 65 of the couples in the study had either suffered more than six unsuccessful embryo transfers or cumulative transfers of more than 15 embryos. They underwent genetic screening as well as other investigations and this revealed a variety of abnormalities in 16 of the women and two of the partners. One woman out of 16 did give birth, a second has an ongoing pregnancy but the other 14 never conceived, had miscarriages or, in one case, had only immature eggs.
Dr Raziel said that other studies had shown that the prevalence of chromosomal abnormalities in infertile men ranged from 2% to 14%, and identifying abnormalities in the partners of two of the 16 women demonstrated that both partners in a fraction of couples will have problems.
He told the conference: "We recommend that for women who suffer repeated implantation failure after IVF, peripheral blood karyotyping should be part of the routine work-up of the couple. Treatment can then be tailored to fit the individual patient's gynaecological background and the type of chromosomal changes detected. That treatment may be pre-implantation genetic diagnosis, further attempts at IVF or oocyte donation when an egg factor is involved."
Abstract no: O-192
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