20世纪90年代起,随着围生医学的迅速发展和新生儿重症监护技术的提高,极低出生体重(VLBW,<1500g)和超低出生体重(ELBW,<1000g)的早产儿存活率明显提高。世界各国低出生体重儿(LBWI)的发生率各不相同,据报道,瑞典为3.71%、美国为7.40%、委内瑞拉为13.30%、印度为28.00%、日本为9.33%[1]。我国近年在6%左右,2006年国内调查LBWI发生率为4.6%,城市为3.9%,农村为 Since the 1990s, the survival rate of preterm infants with very low birth weight (VLBW, <1500g) and ultra-low birth weight (ELBW, <1000g) has been significantly increased with the rapid development of perinatal medicine and the enhancement of neonatal intensive care. improve. The incidence of LBWI varies from country to country, with 3.71% in Sweden, 7.40% in the United States, 13.30% in Venezuela, 28.00% in India and 9.33% in Japan [1]. In recent years, China is at about 6%. In 2006, the incidence of LBWI in China was 4.6%, in urban areas 3.9% and in rural areas