Objective This study utilized the Dr. Foster Global Comparators database to identify pregnancy complications and associated risk factors that led to severe maternal morbidity during delivery hospitalisations in large university hospitals based in the USA, Australia, and England. Design Retrospective cohort. Setting Births in the USA, England and Australia from 2008 to 2013. Sample Data from delivery hospitalisations between 2008 and 2013 were examined using the Dr. Foster Global Comparators database. Methods We identified delivery hospitalisations with life‐threatening diagnoses or use of life‐saving procedures, using algorithms for severe maternal morbidity from the Center for Disease Control. Frequency of severe maternal morbidity was calculated for each country. Main outcome measures Multivariable analysis was used to examine the association between morbidity and socio‐demographic and clinical characteristics within each country. Chi‐square tests assessed differences in covariates between countries. Results From 2008 to 2013, there were 516 781 deliveries from a total of 18 hospitals: 24.5% from the USA, 57.0% from England and 18.4% from Australia. Overall severe maternal morbidity rate was 8.2 per 1000 deliveries: 15.6 in the USA, 5.0 in England, and 8.2 in Australia. The most common codes identifying severe morbidity included transfusion, disseminated intravascular coagulation, acute renal failure, cardiac events/procedures, ventilation, hysterectomy, and eclampsia. Advanced maternal age, hypertension, diabetes, and substance abuse were associated with severe maternal morbidity in all three countries. Conclusion Rates of severe maternal morbidity differed by country. Identification of geographical, socio‐demographic, and clinical differences can help target modifications of practice and potentially reduce severe maternal morbidity. Tweetable abstract Rates of severe maternal morbidity vary, but risk factors associated with adverse outcomes are similar in developed countries.

(Am J Obstet Gynecol. 2019;220:582.e1–582.e11) The pregnancy-related mortality ratio in the United States has tripled between 1987 and 2014. Some studies have estimated 35% to 44% of cases of maternal mortality or severe maternal morbidity are preventable. Hypertensive disorders of pregnancy (HDP) affect 10% of pregnancies worldwide and are one of the main causes of maternal and perinatal morbidity. Cardiovascular (CV) disease is the leading cause of death in women in the United States and the leading cause of pregnancy-related death. HDP have been associated with an increased risk of CV disease 10 to 30 years after delivery, but there is a lack of data on the relationship between HDP and CV morbidity during hospitalization for delivery. This study aimed to identify the risk of CV morbidity during delivery hospitalization in pregnancies complicated by HDP.