复发性流产（RSA）的发生涉及包括遗传、感染、内分泌紊乱、营养缺乏、高凝状态、免疫异常等诸多因素。补体系统是机体先天防卫的重要组成部分，正常水平的补体激活是机体维持正常生理活动的必要机制，但过度的补体系统激活却可以引起病理损伤，导致疾病的发生。近年来，有关研究发现补体激活在抗磷脂综合症相关的流产中起重要作用。我们的前期研究进一步发现补体激活C3a片段是早期复发性流产的一个敏感的生物标记。本研究试图通过检测正常孕育妇女和RSA患者孕前治疗前、孕前治疗后、早孕阶段的C3a等水平，及其与妊娠结局的关系，探讨补体活化片段是否可以成为监测RSA临床发展、转归的指标。并通过流产鼠模型、免疫性疾病鼠模型，研究补体激活在RSA发生、发展和转归中的作用机制，为临床预防、诊断、治疗复发性流产开创新的途径。

Reccurrent spontanous abortion (RSA) may be happened through various factors, including genetic, infectious, endocrinological problems,and immunological factors, as well as hyper-coagulational state. Complement system is a very important part of innate defence for human body. Complement activation at the normal level is a necessary process to keep a normal physiological activities, but the excess activation of complement system may induce pathological damadge and cause the different diseases. In recent years, some studies have found that complement activation play a critical role in the abortions induced by anti-phospholipid antibody syndrom. One of our just-finished studies further identified that complement activation fragment C3a is a sensitive biomarker for early-stage (within first trimester) RSA. This study is designed to detect C3a, ect in the blood plasma from RSA patients at the time before any treatment and pregnancy, after treatment before pregnancy, as well as the beginning of pregancy, in order to see the relationship between complement activation and the fate of pregnancy, and to see if complement activation fragment, such as C3a, may be a marker for the occurance, development, as well as pregnosis of RSA. Furthermore, the mechanism involved in complement activation and RSA will be explored by two mouse models, such as abortion mouse model and rat model with auto immune diseases, so as to explore a clinical new passway for the prevention,treatment as well as prognosis of RSA.