With the increasing accessibility and decreasing cost of high-throughput sequencing，expanded carrier screening （ECS） for autosomal recessive genes is evolving from a targeted test based on ethnicity or family history into a universal preventive medicine tool for the general preconception and prenatal population. This article，grounded in obstetric clinical practice，aims to provide an in-depth exploration of the core value of this technology in contemporary perinatal medicine. The author believes that its significance extends far beyond mere "testing." It fundamentally reshapes the defense system against severe monogenic disorders，enabling a paradigm shift from passive diagnosis to active prevention，and from isolated case management to systematic healthcare intervention. This article will share personal insights and practical experience，focusing on three core values of its clinical application and the key decisions and challenges in its implementation pathway.