Background and Aim Congenital malformations are one of the important reasons of mortality and morbidity in newborns. The aim of this study is to give the frequency and distribution of the congenital malformation in a neonatal intensive care unit from Turkey.

Method A retrospective analysis of congenital abnormalities in singleton births was performed to identify frequency, types, combined congenital abnormalities and distribution of malformation in newborns over a 7 year period. Congenital malformations were classified according to involved organ systems and also classed as single and multiple malformations.

Result 1024 newborns with congenital malformations (13.7%) were identified among the 7450 hospitalized newborns in neonatal intensive care unit (NICU). Mean birth weight was 2988±648gr, mean gestational age was 37.9±2.5 weeks. Consanguinity rate was 22.3%. Prenatal diagnosis rate was 11%. The most affected system was the cardiovascular system (68.8%). Most of the malformations (69.6%) were single malformations while 20.4% of the newborns had multiple major and 8.4% of the newborns had multiple minor malformations. On the other hand, 1.4%, 0.1% and 1.6% of the newborns had deformation, disruption and displasia, respectively. Chromosomal analysis was only performed 24.8% and 65.3% of them were in normal limits. The most frequently detected chromosomal abnormality was Trisomy 21. Overall mortality rate was 15.5% among the newborns with congenital malformations.

Conclusion The most common congenital malformation was cardio-vascular malformations in our hospital. Preventing and prenatal diagnosis of congenital malformations may help to reduce perinatal mortality and morbidity.Therefore, each country should establish its own national database for prevention and management of congenital malformations.