Abstract: Objective：To evaluate the efficiency of the obstetric early warning score (OEWS) from Intensive Care National Audit and Research Centre（ICNARC）Case Mix Program（CMP）（ICNARC-OEWS） for predicting the obstetric critical diseases in peripartal women who admitted to intensive care unit (ICU). Methods: This is a retrospective cohort study on the peripartal women who admitted to ICU with direct and indirect obstetric-related causes at Suzhou Municipal Hospital from Jan 2015 to May 2018. According to ICNARC-OEWS, the score was calculated on the basis of the clinical data collected during the first 24 hours of ICU admission. The aggregate performance of ICNARC-OEWS in predicting the discrimination and risk stratification was evaluated. Results: During the study period, 67 148 deliveries were recorded. There were 214 women who admitted to obstetric ICU, with the rate of ICU admission 3.19/1 000. In total, there were 2 maternal death and 97 severe maternal morbidity, with the rates of the mortality and sever morbidity 2.98/100 000 and 1.44/1 000 respectively. The most frequent causes of ICU admission were the direct obstetrical-related conditions. The OEWS score was significantly higher in women with severe morbidity than those without [7 (6, 9) vs. 4 (1, 5)，Z=－10.340, P=0.000]. Peripartal women with normal OEWS had 0% severe morbidity. The negative predictive value (NPV) in women with 1-3 score of OEWS was 94.5% (52/55), while the positive predictive value (PPV) in women with ≥6 score of OEWS was 79% (83/105). The area under curve (AUC) of the receiver operating characteristic curve (ROC) based on OEWS was used to discriminate the severe maternal morbidity with the efficiency of 0.908 (95%CI: 0.870-0.946, P＜0.001). The AUC values were 0.875 (95%CI：0.784-0.966） and 0.920 (95%CI：0.879-0.961）in the ICU-admitted women with indirect factors and those women with direct factors, respectively (P＜0.001). Conclusions: Our results suggested that the performance of ICNARC-OEWS in the discrimination and risk stratification of severe maternal morbidity was good in those obstetric ICU-admitted women, and that the ICNARC-OEWS could be promoted to use in the obstetric ICU-admitted women.

Key words: Obstetric early warning score system, Intensive care units, Critical care outcomes, Pregnant women, Forecasting