Risk factors for obstetric admissions to the intensive care unit in a tertiary hospital: a case-control study.

Objective: The objective was to review all obstetric admissions to the intensive care unit (ICU) at the Royal Free Hospital, London, UK, and to identify the risk factors for obstetric admissions to the ICU.

Method: We carried out a retrospective case-control study. The cases consisted of women admitted to the ICU during pregnancy and up to 42 days postpartum between 1 January 1993 and 31 December 2003. Controls were women who delivered immediately before and after the indexed case. Demographic data, medical and surgical histories, pregnancy, and intrapartum and postpartum data were collected. Statistical analysis was done using SPSS software.

Results: Thirty-three obstetric patients were admitted to the ICU, representing 0.11% of all deliveries. The ICU utilization rate was 0.81%. Eighty percent of the admissions were postpartum. The main indications for admission were hypertensive disorders (39.4%), and obstetric haemorrhage (36.4%). There was no difference between cases and controls in, age, parity, smoking and employment status. Compared with controls, women admitted to the ICU were significantly more likely to be black (P<0.05), have a shorter mean duration of pregnancy (36.6 vs. 39.2 weeks; P=0.006), delivered by emergency caesarean section (P<0.001), and have higher mean blood loss at delivery (1,173 vs. 296 ml; P<0.001). The risk factors for obstetric ICU admission were black race (odds ratio [OR] =2.8, 95% confidence interval [CI] 1.05-6.28), emergency caesarean section (OR=14.9, 95% CI 5.38-41.45) and primary postpartum haemorrhage (OR=5.4, 95% CI 1.79-4.35).

Conclusion: Women of black race, those delivered by emergency caesarean section and those with primary postpartum haemorrhage are more likely to be admitted to the ICU.