In Norway about 300 babies with a birthweight of 500-999 grams and 200 with a gestational age of 24-27 weeks are born annually. This gives a total of 320-330 babies who come under the definition of extreme prematurity. Obstetric care is important in order to avoid premature birth, or, when premature birth is unavoidable, to find the optimal time and place for delivery. There is ongoing discussion of what constitutes reasonable lower limits for offering life support. The survival rate for babies born before 24 gestational weeks is low and the risk of serious neurological damage high. The risk of severe lung disease is reduced with pre- and postnatal treatment with corticosteroids and postnatal treatment with surfactant, but excessive corticosteroid treatment may possibly increase the risk of neurological damage. Despite major recent progress in the treatment of the preterm baby, significant understanding of why disabilities occur is lacking.