Trisomy 18 has over a hundred different abnormalities that result due to all three forms of this disorder. Full of complete trisomy 18 tends to have the most severe symptoms and a smaller chance of survival. Only about 50% of babies with trisomy 18 live longer than one week and about 5-10% make it to their first birthdays. Heart and kidney abnormalities are extremely common in these cases and are even able to be seen before birth with ultrasound imaging.