Pre-implantation genetic testing (PGT) is offered as an add-on by many UK clinics who claim it gives older women the best chance of motherhood success by screening out embryos with genetic abnormalities.
But a major international study including hundreds of women between the age of 36 and 40 found no difference in their chances of giving birth within a year after having PGT or IVF on its own.
The findings, published in the journal Human Reproduction on Sunday, confirm the beliefs of many fertility experts who say private IVF clinics often “take couples for a ride” with non-evidence based therapies.
In the wake of the research they said women should no longer be offered PGT, which costs nearly £2,000 per cycle at some prominent UK clinics.
Genetic screening takes material from eggs at the earliest stage of embryo development and tests for abnormalities in the chromosomes which carry DNA.
Humans have 23 chromosomes, and having more or fewer than this is a common issue in sex cells that gets worse with age – affecting over 50 per cent of eggs in women over 40.
These abnormalities are the main cause of miscarriage and a major reason why some embryos produced using IVF don’t lead to successful pregnancy after being transferred. PGT works on the principle that negative pregnancies and miscarriages can be minimised by screening these abnormal embryos before they’re implanted.
While NHS clinics screen for genetic diseases PGT is not routinely offered, however the increasing postcode lottery for patients as cash-strapped regions cut funding for IVF cycles means many more people use private services.
It is just one of a range of add-on (adjuvant) therapies and tests which clinics say are necessary to achieve the best results.
However The Independent has revealed how UK fertility watchdogs are highly suspicious of inflated success rates being advertised to UK couples, which some overseas groups claim are as high as 98 per cent.
“All too often couples requiring IVF treatment are taken for a ride when it comes to a bewildering array of unproven tests and adjuvant treatments,” said Professor Jan Brosens, an obstetrics and gynaecology expert at the University of Warwick, who was not involved in the study.
“This smartly designed and well conducted study was designed to give couples clear-cut information on whether PGT-A increases the chance of having a baby within one year.
“The answer is no.”
The study, which followed 396 women across nine fertility centres in seven countries, randomly allocated half the participants have either abnormality screening through PGT, or just IVF.
The number of women who had a live birth within 12 months of the study was identical in both groups, at 24 per cent. It did find that women who had PGT screening were significantly less likely to have a miscarriage and this may be enough to sway some couples.
“Many IVF clinics may well erroneously seize this as a ‘selling point’ for PGT-A,” said professor of reproductive medicine at the University of Southampton, Ying Cheong, who was not involved in the study.
“It needs to be emphasised that these are secondary end-points which the study was not powered to definitively answer and so must be interpreted with caution.
She said biopsies of embryos for PGT if there was no evidence it worked “is poor clinical practice”, adding: “We still do not understand fully the developmental biology of the egg and the embryo, and as such, may cause more harm than good.
“For these reasons, it is my opinion that PGT-A should not be offered to women with advanced maternal age.”
Join our new commenting forum
Join thought-provoking conversations, follow other Independent readers and see their replies