Tracking embryo implantation using cell-free fetal DNA enriched from maternal circulation at 9 weeks gestation.

Embryo DNA fingerprinting represents an important tool for tracking embryo-specific outcomes after multiple embryo transfer during IVF. The situation in which two embryos are transferred and only one implants represents a unique opportunity for the most well-controlled validation of markers capable of identifying competent and incompetent embryos. Specifically, this design eliminates all patient-related variables from the comparison of embryos with or without reproductive potential. However, in order to determine which embryo implanted, the investigator must wait until newborn DNA is available upon delivery. This study validates a non-invasive cell-free fetal DNA fingerprinting method that reduces the time to identify which embryo implanted by ∼31 weeks. Thirty-four patients were studied to determine if fingerprinting of fetal DNA extracted from maternal plasma at nine gestational weeks concurred with the buccal DNA results obtained from the newborn after delivery. This validation required single nucleotide polymorphism profiles on each couples' preimplantation embryos, cell-free fetal DNA from maternal plasma at 9 weeks gestation, and newborn DNA obtained from buccal swabs after delivery. The predictions from fetal DNA-based embryo tracking and gender assignments made at 9 weeks gestation were 100% consistent with standardized methods of assessment performed after term delivery. This study demonstrates the first validated fetal DNA fingerprinting method which predicts both gender and which embryo implanted at 9 weeks gestation following multiple embryo transfer.