Epidemiology of Pregnancy-Associated ICU Utilization in Texas: 2001 - 2010

ICU admission is uncommon among obstetric patients. Nevertheless, the epidemiology of ICU utilization is considered to be a useful proxy for study of severe maternal morbidity and near-miss events. However, there is paucity of population-level studies in obstetric patients in the United States.

The Texas Inpatient Public Use Data File and state-based reports were used to identify pregnancy-associated hospitalizations and those involving admission to ICU (n = 158,410) for the years 2001 - 2010. The clinical characteristics, outcomes, and the overall incidence and temporal trends of ICU admission were examined and stratified analyses of pregnancy outcomes were performed in specific categories of pregnancy-associated hospitalizations. In addition, ICU utilization among hospitalizations with maternal complications and organ dysfunction was evaluated.

Chronic comorbidities (9.7%) and presence of organ dysfunction (6.2%) were uncommon among ICU admissions, with 26.5% having high severity of illness. The incidence of ICU admission was 39.0 per 1,000 pregnancy-associated hospitalizations-years. Marked variability was found in ICU admission both across pregnancy outcomes (ranging from 0.6 per 1,000 abortions-years to 85.9 per 1,000 stillbirths-years) and categories of pregnancy-associated hospitalizations (ranging from 32.1 per 1,000 delivery hospitalizations-years to 144.8 per 1,000 postpartum hospitalizations-years). The incidence of ICU admission rose 68% among pregnancy-associated hospitalizations and for all examined subgroups, except abortion. Preeclampsia/eclampsia (23.3%) and obstetric hemorrhage (6.9%) were the most common maternal complications among ICU admissions. Four hundred fourteen women (0.3%) died, while 97.6% were discharged home.

This study documents the highest incidence of ICU utilization in obstetric patients in the US to date. The findings suggest low threshold for obstetric ICU admissions in the state and do not support comparative use of ICU utilization as surrogate measure for populations' burden of severe maternal morbidity and near-miss events. Nevertheless, the demonstrated tremendous heterogeneity in ICU utilization across examined subgroups identifies new high-risk groups of obstetric patients that would benefit from heightened clinician vigilance and timely ICU triage and care. Further studies are needed to inform reduction in avoidable variability in ICU utilization to both enhance maternal, fetal, and neonatal outcomes and to improve resource allocation.