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.
Preimplantation genetic screening in women of advanced maternal age caused a decrease in clinical pregnancy rate: a randomized controlled trial.
Advanced maternal age (AMA) is an important parameter that negatively influences the clinical pregnancy rate in IVF, in particular owing to the increased embryo aneuploidy rate. It has thus been suggested that only transferring euploid embryos in this patient group would improve the pregnancy rate. The purpose of this study was to test whether employing preimplantation genetic screening (PGS) in AMA patients would increase the clinical pregnancy rate.
                We conducted a two-center, randomized controlled trial (RCT) to analyze the outcome of embryo transfers in AMA patients (>or=38 years of age) after PGS using FISH analysis for chromosomes X, Y, 13, 16, 18, 21 and 22. The PGS group was compared with a control group. The primary outcome measure was clinical pregnancy rate after 6-7 weeks of gestation per randomized patient.
                The study was terminated early as an interim analysis showed a very low conditional power of superiority for the primary outcome. Of the 320 patients calculated to be included in the study, 56 and 53 patients were randomized into the PGS and control groups, respectively. The clinical pregnancy rate in the PGS group was 8.9% (95% CI, 2.9-19.6%) compared with 24.5% (95% CI, 13.8-38.3%) in the control group, giving a difference of 15.6% (95% CI, 1.8-29.4%, P = 0.039).
                Although the study was terminated early, this RCT study provides evidence against the use of PGS for AMA patients when performing IVF. Trial registration number: ISRCTN38014610.