ADVANCE Study: Assay Development and Validation for Pre-Natal and Obstetric Conditions

BillionToOne Inc. is conducting a large prospective study to evaluate the performance of a non-invasive circulating fetal cell (CFC) assay. Circulating fetal cells, rare, intact trophoblast cells of placental origin present in maternal blood, offer a unique opportunity to directly analyze fetal genetic material without the need for invasive procedures. These cells are most abundant during the first trimester of pregnancy.

Building on this biology, the investigators developed a circulating fetal cell assay (UNITY Confirm) that isolates fetal-derived placenta cells from maternal blood and performs single-cell genomic analysis to assess chromosomal copy number. By combining cell-type-specific markers and genotyping to distinguish fetal from maternal cells, this approach enables direct evaluation of fetal chromosomal status, unlike cfDNA methods that rely on analysis of mixed DNA fragments.

This prospective study enrolls pregnant individuals between 10 and 20 weeks of gestation with singleton pregnancies and aims to include over 1,000 participants. CFC testing results are compared to prenatal or postnatal diagnostic outcomes.