Screening early stage embryos to avoid implanting those with genetic defects does not improve pregnancy rates of older women undergoing in vitro fertilization (IVF) and might even reduce the likelihood of a successful pregnancy, according to a multicenter, randomized controlled, double-blind trial by Dutch researchers (Mastenbroek S et al. N Engl J Med. 2007; 357:9-17).
The investigators discovered that a group of 206 women randomly assigned to preimplantation genetic screening had, compared with a control group of 202 women, significantly lower ongoing (lasting 2 weeks or longer) pregnancy rates (25% vs 37%, respectively) and live birth rates (24% vs 35%, respectively).
Stephenson J. Screening Early Embryos. JAMA. 2007;298(7):731. doi:10.1001/jama.298.7.731-c