Screening 'reduces success of IVF' in older women
Birth rates were lower in the PGS group
Wednesday, 04, Jul 2007 11:12
Preimplantation genetic screening (PGS) reduces ongoing pregnancy and live birth rates in women over 35 undergoing IVF treatment, according to new research.
A study presented at the European Society of Human Reproduction and Embryology conference and published in the New England Journal of Medicine suggested that PGS should not be routinely used in women of advanced maternal age.
The research, by a team from the University of Amsterdam's centre for reproductive medicine, involved a randomised trial featuring IVF cycles with a group of women given PGS and a group that were not given the screening.
Of the 408 women aged between 35 and 41 taking part in the trial, 206 were given PGS and 202 were not. The team found that after 12 weeks, 25 per cent of the PGS group were pregnant compared to 37 per cent of the control group.
Furthermore the women in the PGS group also had a significantly lower birth rate, with 24 per cent of PGS women giving birth compared to 35 per cent in the other group.
Commenting on why PGS has this effect, Sebastiaan Mastenbroek, from the University of Amsterdam team, said: "It is possible that the biopsy of a cell from an early embryo on day three after conception hampers the potential of an embryo to successfully implant, though the effect of biopsy alone on pregnancy rates has not been studied."
The researchers added that the limitation on the number of chromosomes that can be analysed could lead to the transfer of embryos that appear normal but are actually abnormal.
PGS is a recent technique that is increasingly being used in IVF centres throughout the world.
According to the University of Amsterdam report, 45 per cent of clinics surveyed in the US reported that 2,197 cycles of PGS were performed in 2005.
Mr Mastenbroek added that the idea of screening embryos to increases birth rates in IVF is "very plausible" and the team would now investigate why it does not work.