Tehran University of Medical Sciences Acta Medica Iranica 0044-6025 51 5 2013 05 15 297 302 EN Fatemeh Nayeri Neonatologist, Maternal-Fetal-Neonatal Research Center ,Tehran University of Medical Sciences, Tehran, Iran. Hosein Dalili Neonatologist, Breastfeeding Research Center ,Tehran University of Medical Sciences, Tehran, Iran. Firoozeh Nili Neonatologist, Maternal-Fetal-Neonatal Research Center ,Tehran University of Medical Sciences, Tehran, Iran. Elaheh Amini Neonatologist, Breastfeeding Research Center ,Tehran University of Medical Sciences, Tehran, Iran. Ali Ardehali General Physician, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran. Babak Khoshkrood Mansoori General Physician, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran. Mamak Shariat Maternal & Child Health Specialist, Maternal-Fetal-Neonatal Research Center, Tehran University of Medical Sciences, Tehran, Iran. 2015 10 11 The objective of this study is to determine risk factors causing increase in very low birth way (VLBW) neonatal mortality. The medical files of all neonates weighing ≤1500 g, born in Vali-e-Asr hospital (2001-2004) were studied. Two groups of neonates (living and dead) were compared up to the time of hospital discharge or death. A total of 317 neonates were enrolled. A meaningful relationship existed between occurrence of death and low gestational age (P=0.02), low birth weight, lower than 1000 g (P=0.001), Apgar score <6 at 5th minutes (P=0.001), resuscitation at birth (P=0.001), respiratory distress syndrome (P=0.001) need for mechanical ventilation (P=0.001), neurological complications (P=0.001) and intraventricular hemorrhage (P=0.001). Regression analysis indicated that each 250 g weight increase up to 1250 g had protective effect, and reduced mortality rate. The causes of death of those neonates weighting over 1250 g should be sought in factors other than weight. Survival rate was calculated to be 80.4% for neonates weighing more than 1000 g. The most important high risk factors affecting mortality of neonates are: low birth weight, need for resuscitation at birth, need for ventilator use and intraventricular hemorrhage. https://acta.tums.ac.ir/index.php/acta/article/view/4443 https://acta.tums.ac.ir/index.php/acta/article/download/4443/4580