Recurrent pregnancy loss (RPL) is one of the most frustrating, yet poorly understood areas in reproductive medicine. The prevailing theory is that RPL is triggered by a spectrum of conditions varying from anatomic factors, autoimmune disorders, endocrine dysfunction, thrombophilia, to maternal infections that may possibly harm a vulnerable early pregnancy, leading to a miscarriage.
However, the etiology is often unknown and evidence-based diagnostic and treatment tools are practically nonexistent. Published articles evaluating the etiology, assessment, and management of RPL do have fundamental deficiencies due to ascertainment bias and improper selection of controls.
Pregnancy losses can be attributed to a prevalence of chromosomal abnormalities in the embryo. Genome-wide screening of individual blastomeres have shown that up to 70% of high-quality cleavage-stage embryos obtained with in vitro fertilization (IVF) procedures contain cells with structural chromosomal imbalances, some caused by meiotic aneuploidies but most by mitotic nondisjunction (1).
Although the aneuploidy rate will decline from the cleavage to the blastocyst stage, many embryos will be aneuploid and present a possible cause for implantation failure or miscarriage.