Therapeutic advances in neonatology cause fewer hypoxic conditions. In relation with this we observe fewer high grade brain haemorrhages. Therefore, ischemical brain changes through brain oedema (12%) and resulting colliquation necroses become the focal point of diagnostic and therapeutic work. 7.3% of intensively treated neonates showed the sonographic picture of a periventricular leucomalacy (PVL). The polycystic areas can be seen on the eight day after birth at the earliest and at six months they turn into a glia scar which is not very obvious on the sonograph. We found a relation between beta-mimetic tocolysis, hypocapnia and the development of a PVL. We were not able to prove statistically a connection with premature birth.