PGS as currently performed significantly decreases live birth rates in women of advanced maternal age and those with repeated IVF failure. Trials in which PGS was offered to women with a good prognosis suggested similar outcomes. PGS technique development is still ongoing in an effort to increase its efficacy. This involves biopsy at other stages of development (polar body or trophectoderm biopsy) and other methods of analysis (comparative genome hybridisation (CGH) or array-based technologies) than used by the trials included in this review. These new developments should be properly evaluated before their routine clinical application. Until such trials have been performed, PGS should not be offered as routine patient care in any form.
A prospective randomized controlled trial of preimplantation genetic screening in the "good prognosis" patient.
To determine whether the routine use of preimplantation genetic screening (PGS) in "good prognosis" women improves in vitro fertilization (IVF) cycle outcome.
                Randomized, controlled, prospective clinical study.
                Private infertility clinic.
                Infertile women predicted to have a good prognosis as defined by: age <39 years, normal ovarian reserve, body mass index <30 kg/m(2), presence of ejaculated sperm, normal uterus, <or=2 previous failed IVF cycles.
                Patients were randomized to the PGS group or the control group on day 3 after oocyte retrieval; 23 women underwent blastomere biopsy on day 3 after fertilization (PGS group), and 24 women underwent routine IVF (control group). All embryos were transferred on day 5 or 6 after fertilization.
                Pregnancy, implantation, multiple gestation, and live birth rates.
                No statistically significant differences were found between the PGS and control groups with respect to clinical pregnancy rate (52.4% versus 72.7%). However, the embryo implantation rate was statistically significantly lower for the PGS group (31.7% versus 62.3%) as were the live birth rate (28.6% versus 68.2%) and the multiple birth rate (9.1% versus 46.7%).
                In a "good prognosis" population of women, PGS does not appear to improve pregnancy, implantation, or live birth rates.