Controversial embryo screening method improves live birth rates
Preimplantation genetic testing for aneuploidy, or PGT-A, improved in vitro fertilization success rates and guarded against miscarriage, despite guidance suggesting that it is not effective or safe, according to researchers.
Fertility clinics use PGT-A to screen for gross genetic abnormalities in human IVF embryos. While supporters say the treatment is effective and safe, others say randomized clinical trials have not established its safety or efficacy and that patients should not be subjected to it, especially since they have to pay for it.
The Human Fertilisation and Embryology Authority (HFEA) in the United Kingdom agreed that PGT-A’s safety and efficacy have not been established and gave the practice two “red lights” in the past, but recently changed that rating to one red light.
The researchers used freedom of information requests to acquire data from HFEA about PGT-A and non-PGT-A cycle outcomes from 2016 to 2018. The retrospective cohort analysis examined the differences between these groups but without controlling for confounders besides maternal age, which the researchers called the leading known risk factor for chromosome abnormalities. Fresh and frozen transfers were included as well.
“This data will hopefully aid the HFEA in their continual surveillance of the ‘red traffic light’ guidance that currently states there is no evidence that PGT-A is effective or safe,” author Darren Griffin, PhD, professor of genetics at the University of Kent, said in a press release.
The data included total number of cycles, cycles with no embryo transfer, total number of embryos transferred, live birth rate (LBR) per embryo transferred and LBR per treatment cycle. There were 2,464 PGT-A procedures out of a total of 190,010 cycles (1.3%).
The researchers said the LBR per embryo transferred and the LBR per treatment cycle — including cycles with no transfer — was significantly higher for all PGT-A age groups than non-PGT-A age groups, including those aged younger than 35 years (P < .05). Also, LBR for patients aged older than 40 years were three to 11 times greater with PGT-A than without.
Furthermore, the researchers found a reduced number of transfers per live birth, particularly for women aged older than 40 years, implying that patients became pregnant faster when PGT-A was used, the researchers said.
Despite these benefits, the researchers said, they noted that their study was limited in matching complete clinical indication information with its PGT-A and non-PGT-A cohorts.
“The guidance could be revised in the light of this new data for patient benefit. I appreciate the collegial way in which the HFEA have assisted in providing this data and their open-mindedness to the prospect of revisiting their guidance and traffic light system,” Griffin said.