International Perspectives

Abstract

Since 1984, Tokyo Women’s Medical University has played a pioneering role in improving the treatment results of ultrapreterm infants in Japan. The results were cited in the newest edition of Avery’s Neonatology: Pathophysiology & Management of the Newborn . (1) Like many western countries, the survival rate of extremely low-birthweight (ELBW) and very low-birthweight (VLBW) infants improved in Japan in the 1990s, with the spread of new treatment methods such as surfactant therapy, new methods of mechanical ventilation such as high-frequency oscillatory ventilation (HFOV), and prenatal steroid therapy. (2) The Committee on Newborn Infants, Japan Society of Pediatrics, has performed nationwide surveys on the outcomes of ELBW and VLBW infants for reports on the current status of neonatal intensive care units and overall neonatal mortality in Japan at 5-year intervals since 1980. The mortality rate of infants weighing less than 1,000 g at birth significantly declined in the previous 2 decades from 55.3% in 1980 and 28.2% in 1990 to 17.8% in 2000 (Table⇓). In view of this, the Ministry of Health, Labor and Welfare of the Japanese government changed the definition of the threshold of viability in the Maternal Protection Law from 24 weeks of gestation to 22 weeks of gestation in January 1991. After this change, neonatologists in Japan have increasingly intervened in deliveries at 22 to 23 weeks of gestation. | Year | Number of Survivors/Number of Admissions | |:------:| ---------------------------------------- | ----------------- | | <500 g | 500 to 999 g | 1,000 to 1,499 g | | 1980 | 0/0 | 493/1,102 (45%) | 2,633/3,319 (79%) | | 1985 | 5/52 (10%) | 1,085/1,846 (59%) | 3,695/4,180 (88%) | | 1990 | 9/50 (18%) | 1,462/2,000 (73%) | 3,524/3,786 (93%) | | 1995 | 39/132 (30%) | 1,789/2,298 (78%) | 4,139/4,355 (95%) | | 2000 | 57/153 (37%) | 2,238/2,638 (85%) | 4,844/5,036 (96%) | Table. Survival Rates of Infants Weighing Less than 1,500 g at Birth in Japan Although Sumida and associates (3) and Tsuchida and colleagues (4) reported in 1999 and 2001, respectively, survival rates at 22 weeks’ gestation of approximately 30%, their results were published in Japanese, and the number of patients was small. At the Hot Topics in Neonatology conference (Washington, DC) in 2002, Nishida reported the outcomes of infants born at 22 to 23 weeks of gestation …