早产(preterm delivery,PTD)是指妊娠满28周至不足37周(196～258日)的分娩,是新生儿患病和新生儿死亡的主要因素。早产的病因和发病机制尚未完全明确,目前认为早产是由内分泌、免疫等多个系统相互作用产生的综合征。在早产的病程中,细胞因子、激素、酶及蛋白质分解酶等多因子参与, Preterm delivery (PTD) refers to delivery between 28 weeks and less than 37 weeks (196 to 258 days) of pregnancy, and is a major cause of neonatal morbidity and neonatal death. The etiology and pathogenesis of prematurity has not yet been fully defined, premature birth is currently considered by the endocrine, immune and other systems arising from the interaction syndrome. In the course of prematurity, cytokines, hormones, enzymes and proteolytic enzymes and other factors involved,