title: Mortality rates for extremely low birth weight infants born in Japan in 2005.
abstract: OBJECTIVE
  Our goal was to investigate the neonatal mortality rate and the mortality rate during the NICU stay for extremely low birth weight infants born in Japan in 2005.
  
  
  METHODS
  The Committee of Neonatal Medicine of the Japan Pediatric Society retrospectively surveyed the deaths of extremely low birth weight infants born and hospitalized between January 1 and December 31, 2005. From 297 institutions in Japan, data on 3065 extremely low birth weight infants, which represented 98.4% of those reported in the maternal and health statistics of Japan in 2005, were collected.
  
  
  RESULTS
  The neonatal mortality rate and the mortality rate during the NICU stay were 13.0% and 17.0%, respectively, which were lower than 17.7% and 21.5% in the survey in 2000. The neonatal mortality rates and the mortality rates during the NICU stay were 53.3% and 67.7% in the <400-g birth weight group (n = 62), 42.1% and 53.5% in the 400- to 499-g birth weight group (n = 159), 22.2% and 27.7% in the 500- to 599-g birth weight group (n = 387), 16.8% and 22.2% in the 600- to 699-g birth weight group (n = 537), 9.4% and 12.7% in the 700- to 799-g birth weight group (n = 574), 6.3% and 9.1% in the 800- to 899-g birth weight group (n = 649), and 3.9% and 5.3% in the 900- to 999-g birth weight group (n = 697), respectively. The factors involved in the deaths of extremely low birth weight infants included lower gestational age, lower birth weight, male gender, multiple birth, institutions in which <10 extremely low birth weight infants were admitted per year, and no prenatal maternal transfer.
  
  
  CONCLUSIONS
  The mortality rates of extremely low birth weight infants who were born in 2005 demonstrated definite improvement.
authors.affiliation: Department of Pediatrics, Showa University School of Medicine, 1-5-8 Hatanodai, Shinagawa-ku, Tokyo 142-8666, Japan. kitaba@med.showa-u.ac.jp
authors.forename: Kazuo
authors.initials: K
authors.lastname: Itabashi
authors.forename: Takeshi
authors.initials: T
authors.lastname: Horiuchi
authors.forename: Satoshi
authors.initials: S
authors.lastname: Kusuda
authors.forename: Kazuhiko
authors.initials: K
authors.lastname: Kabe
authors.forename: Yasufumi
authors.initials: Y
authors.lastname: Itani
authors.forename: Takashi
authors.initials: T
authors.lastname: Nakamura
authors.forename: Masanori
authors.initials: M
authors.lastname: Fujimura
authors.forename: Masafumi
authors.initials: M
authors.lastname: Matsuo
mesh_terms: D005260:Female; D017052:Hospital Mortality / Q000639:trends*; D006801:Humans; D007226:Infant Mortality / Q000639:trends*; D052577:Infant, Extremely Low Birth Weight; D007231:Infant, Newborn; D007362:Intensive Care Units; D007564:Japan; D008297:Male; D012189:Retrospective Studies