Background: Human preimplantation embryos generated through in vitro fertilization (IVF) or intracytoplasmic sperm injection (ICSI) treatments show a variable rate of numerical chromosome abnormalities or aneuploidies. Preimplantation genetic screening (PGS) has been designed to screen for aneuploidies in high risk patients, with the aim of improving live birth rates in IVF/ICSI. We assessed whether the effect of PGS on live births rates differs in women of advanced maternal age with variable risks for embryonic aneuploidy, and weighed these effects against the results obtained after IVF/ICSI without PGS.
Methods: The effect of PGS on live birth rates was compared between groups defined by maternal age, number of previous miscarriages, semen quality, total amount of recombinant FSH (rFSH) administered during ovarian stimulation and total number of top-quality embryos, using data from a randomized controlled trial among women of advanced maternal age (35-41 years).
Results: There was no significant differential effect of PGS in groups based on maternal age (P-value of interaction 0.16), the number of previous miscarriages (P-value of interaction 0.93), semen quality (P-value of interaction 0.26), rFSH dose (P-value of interaction 0.15) or the number of top-quality embryos (P-value of interaction 0.59). Live birth rates after IVF/ICSI with PGS were lower in all groups when compared with live birth rates after IVF/ICSI without PGS.
Conclusions: The paradigm that the effect of PGS is determined by a woman's risk for embryonic aneuploidy seems incorrect. In fact, PGS has no clinical benefit over standard IVF/ICSI in women of advanced maternal age regardless of their risk for embryonic aneuploidy.