Main causes of peritonitis included spontaneous gastric perforation (23; 25.8%), necrotizing enterocolitis (NEC) (18; 20.2%), spontaneous intestinal perforation (9; 10.1%), volvulus (9; 10.1%), Intestinal atresia (6; 6.7%), Hirschsprung's disease (5; 5.6%), meconium ileus (1; 1.1%), perforation of Meckel's diverticulum (1; 1.1%).