Since placental functions are severely disturbed in miscarriages [77,78,79,80,81,82,83], here, our aim was to determine the changes in concentrations of three known placental biomarker proteins: the free beta-subunit of human chorionic gonadotropin (free β-hCG), pregnancy-associated plasma protein-A (PAPP-A), and placental growth factor (PlGF), and their combinations in women with RPL. The gene discussed is PAPPA; the disease is spontaneous abortion.