During the period 1.1.1986-31.12.1988, the number of patients with severe preeclampsia referred to the intensive care unit in Sønderborg Hospital increased. On the basis of a retrospective study of the hospital records, possible reasons and certain characteristics of this increase are pointed out. Failure of treatment of severe hypertension and oliguria were the most frequent reasons for referral. Respiratory complications predominated: four women had pulmonary oedema and eight required ventilatory support. Despite difficulties in assessing the haemodynamic status, these nineteen cases appear to illustrate the unpredictable variation in severe preeclampsia per se. Insufficient volume expansion may explain a few episodes of oliguria, but neither excessive volume expansion nor unacceptable delay in observation appear to offer plausible explanations for the increase observed. The authors conclude that the frequency of haemodynamic complications in this analysis illustrated the potentially disastrous effect of preeclampsia in itself. Early delivery should always be considered in patients with even minor symptoms of treatment failure, regardless of the age of gestation. Should haemodynamic complications occur despite this, referral to an intensive care unit should be considered.