**1. Introduction**

Prematurity is a significant risk factor for survival of the neonate and is related to increased perinatal mortality and morbidity. Current minimal age of viability is considered to be 22–23 weeks' gestation with dispersed reports of survival earlier than this estimated gestational age (GA) [1].

Extremely low birth weight infants (ELBW) are defined by birth weight of less than 1000 g; also, are the youngest premature newborns typically born at 27 weeks' gestation or younger [1].

Attention has turned to the improvement of the intact survival rate of extremely low birth weight infants (ELBW), particularly of those born at the boundaries of current perinatal medicine. Survival rates to hospital discharge of above 80% have been reported in Canada, USA and Japan for the 25 GW [2–4]. Developed centers report on increase survival rates also for infants born at 23–24 GW [4]

with significant variability in survival observed in resource limited centers [5, 6]. Factors found to be significantly positively correlated with improved survival and outcome of ELBW infants were: older gestational age [1, 5, 6], higher birth weight [1, 5–7], female gender [7], singleton birth [7], antenatal steroid use [1, 6–8], Apgar score at 5 min [1] and delivery by cesarean section (CS) [1, 6]. On the other hand, vaginal delivery in non-vertex presentation [1, 9, 10] placental abruption [1] and the existence of fetal growth restriction [11] have been recognized as adverse factors. Reports highlight birth weights of >750 g in association with better survival [1, 6, 12]. In our previous study, not only that we found a strong positive correlation of higher birth weights with survival, but also of broader head circumferences; the median head circumference was 2.5 cm larger for the survivors [12]. Apgar scores' median value 5 at the first minute were significantly positively associated with favorable outcome [12]. A significant correlation of caesarean section delivery with the outcome has been observed in studies [1, 6, 12], with a higher share of emergency cesarean sections in survivors [12] pointing out that CS is indeed a protective mode of delivery. However, indication of CS in pregnancies of less than 24 weeks is a matter of inclusive worldwide debate. To reach a conclusion, a nationwide survey is needed.

Although the mortality rate has significantly diminished with improved neonatal technologies, use of exogenous surfactant preparations and better understanding of pathophysiology of ELBW infants, the proportion of surviving infants without sequelae, such as chronic lung disease, cognitive delays, cerebral palsy and neurosensory deficits has not improved as noticeably [13, 14].
