早产发生率在不同国家和地区,不同种族和社会状况会有所不同,一般在5%~10%。早产是造成围产儿死亡和婴幼儿伤残的主要原因之一,但是真正导致最大危害的还是占早产比例较小的极低出生体质量儿(VLBWI,出生体质量1500g),特别是超低出生体质量儿(ELBWI,出生体质量1000g)。但是,在 Prevalence of preterm birth in different countries and regions, different racial and social conditions will be different, generally 5% to 10%. Premature delivery is one of the main causes of perinatal deaths and infant and young child disability, but the very real cause of the greatest harm is the very low birth weight (VLBWI, birth weight 1500 g), which accounts for a small proportion of preterm births, especially low births Body mass (ELBWI, birth weight 1000g). But when