Introduction: Based on to date data, more than one in 10 neonates are born preterm worldwide. According to World Health Organization (WHO), incidence of preterm birth ranges from 5% in European countries to 15% in African countries and Africa and South Asia account for 60% of them. Based on a review study in 2015, the incidence rate of preterm birth in Iran of preterm birth worldwide, critical care in the first days after birth is a key factor in survival of preterm newborns. Preterm birth is defined as livebirth that occurs before 37 completed weeks or 259 days of gestation.1