Association of ovarian stimulation and embryonic aneuploidy in in vitro fertilization cycles with preimplantation genetic testing: A narrative systematic review

The impact of gonadotropins used for COS on the rate of embryo aneuploidy in patients without the negative effects of age as a confounding factor, is still a subject of lively debate. We ran a systematic search for studies in MEDLINE, PubMed, Google Scholar and the Cochrane Library. A librarian coordinated the search in December of 2020. We included all original peer-reviewed papers in English, irrespective of study-design. There were no restrictions concerning method of amplification or platform used to analyze the amplified DNA. We used the PICO model to select the study population. We included women/couples submitted to COS for IVF with the intention to genetically analyze her/their embryos through PGT. The primary outcome was the rate of aneuploidy. We used the Newcastle-Ottawa scale (NOS) score to evaluate the quality of the studies included. The search yielded 73 citations, and 14 were eligible for analysis, which included data on 4805 cycles. Media quality NOS score was 8. Although it has been demonstrated that natural cycles are associated with aneuploidy, it does seem that more robust stimulations are indeed associated with a higher proportion of aneuploidy. Nevertheless, a higher response is associated with an increased number of euploid embryos available for transfer, which translates into more embryo-transfer cycles with a prospective higher cumulative live birth rate. Further evidence is needed to ascertain if there is a negative impact of COS, especially at the cellular level.