OP05.02: Fetal fraction of cell‐free DNA in frozen‐thawed and fresh embryo transferred IVF patients

Non-invasive prenatal testing (NIPT) for IVF treated-women is sparsely investigated but a few studies indicate a decrease in fetal fraction (FF) of cell-free DNA for this group. As FF is an important parameter for NIPT test performance, the relevance is high. The study includes patients from the “Freeze All” project at the Fertility Clinics at Hvidovre Hospital and Rigshospitalet, which is a randomised study with transfer of a fresh embryo in an exogenous stimulated cycle or a frozen thawed embryo transfer in a following natural cycle. Blood samples for NIPT analysis have been drawn from pregnant participants between 11 + 0 and 14 + 2 weeks of gestation and analysed at Hvidovre Hospitals NIPT Center. We have included 26 NIPT samples from pregnant women treated with fresh embryo transfer and 27 from pregnant women treated with frozen-thawed embryo transfer. NIPT analysis for the included patients have been compared with a control group of 238 naturally conceived pregnancies with a high-risk result from the combined first trimester screening. The FF was estimated by the SeqFF method. Primary analysis indicates that FF is significantly reduced for IVF-treated pregnant women (FF = 0.056) compared to naturally conceived pregnant women (FF = 0.072) (P = 0.0004) The significance persists through multivariate analysis (P < 0.0001). Furthermore, primary analysis indicates the reduction in FF to be more prominent for IVF patients who received a fresh embryo-transfer (FF = 0.049) compared to those who received a frozen-embryo transfer (FF = 0.063) (P = 0.037). As the study indicates a significant reduction in FF in IVF-patients, special precautions and interpretations seem to be needed for this group. Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.