In this study, the objective was to describe and analyse reasons for obstetric admissions to the ICU, severity of illness, level and types of interventions, adverse events and patient outcomes. In a retrospective database study, we identified 291 obstetric patients during pregnancy and puerperium from four Finnish university hospitals. Most were admitted in the post-partum period and hypertensive disorders were the main indications for admissions, followed by obstetric haemorrhage. The median length of stay was 21hours. The most common intervention was blood transfusion and mechanical ventilation was required in nearly one fifth of the patients. Three patients had a prolonged stay and nine had re-admissions. One maternal death was recorded. This study found that severity of illness and organ failure scores describe the obstetric patient as having a good probability of recovery and a short length of stay. However, the obstetric patients reason for admission and their type of delivery were associated with both the severity of illness scores and level of intervention required. Those admitted for non-obstetric reasons and having had a vaginal delivery demonstrated higher severity of illness scores, organ failure scores, and levels of intervention when compared to those admitted for obstetric reasons or those who had delivered by caesarean section. In conclusion, care of these patients can be improved by understanding the severity of illness scores, common ICU interventions and patient outcomes.