不明原因复发性流产(URSA)是一种病理性妊娠，其病因和发病机制一直是生殖领域研究的热点。近年研究发现，环状RNA(circRNA）作为一类非编码RNA新家族,在胚胎生长发育过程中起重要的调控作用。我们前期研究发现circ-ERBB2、miR-34b-5p、ACER2与URSA存在相关性，通过生物信息学预测发现circ-ERBB2可能靶向miR-34b-5p/ACER2参与胚胎发育调控，根据这一发现及最新研究成果,我们推测：Circ-ERBB2/miR-34b-5p/ ACER2通路参与胚胎发育调控机制,因此本课题从临床研究、动物实验和细胞实验逐步深入论证circ-ERBB2对胚胎发育的影响,阐明circ-ERBB2可能作为竞争性RNA(ceRNA）结合miR-34b-5p调控网络，从而调控ACER2影响滋养细胞的自噬与凋亡平衡，导致胚胎停育，为防治URSA提供理论基础及新的药物靶点。

Unexplained recurrent spontaneous abortion (URSA) is a pathological pregnancy whose etiology and pathogenesis have been the research focus in human reproduction. In recent years, it has been found that circular RNA(circ RNA), as a new family of non-coding RNAs, plays an important role in the regulation of embryonic development. Our previous study found that circ-ERBB2, miR-34b-5p, and ACER2 had correlation with URSA. It is predicted by bioinformatics that Circ-ERBB2 may target miR-34b-5p/ACER2 to participate in the regulation of embryonic development. Based on the latest research results, we hypothesize that the Circ-ERBB2/miR-34b-5p/ACER2 pathway is involved in the regulation of embryonic development in early pregnancy. Therefore, this study gradually clarifies that circ-ERBB2 may act as a competitive endogenous RNA(ceRNA) of miR-34b-5p to regulate ACER2 and affect the autophagy and apoptosis balance of trophoblasts, which finally lead to embryonic arrest by clinical research, animal experiments and cell experiments. This study will provide a theoretical basis and a new therapeutic target for the prevention and treatment of URSA.