Expanded Definition of Severe Maternal Morbidity May ID At-Risk Patients Better

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Amid rising Rates of severe maternal morbidity, 2 new studies consider how to optimize maternal care.

Two new studies on severe maternal morbidity (SMM) from University of Pennsylvania Perelman School of Medicine researchers were presented in poster sessions at the American College of Obstetrics & Gynecology Annual Clinical and Scientific Meeting in Washington, DC, on May 16, 2016. The definition of SMM covers serious bleeding, eclampsia convulsions, heart attacks, emergency hysterectomies, and other potentially fatal crises in women around the time of delivery.

There are approximately 50,000 cases of SMM each year in the United States, and the incidence has been rising. The first study found that widespread adoption of an “expanded” definition of SMM could identify more at-risk patients, saving lives and leading to improved care. The second study, which looked at the relationship between SMM and maternal level-of-care designations at hospitals, suggests a need for better data.

The first study examined the rates and causes of SMM during 1 year of deliveries (July 2014 through June 2015) at the Hospital of the University of Pennsylvania.


Using a more “restricted” definition of SMM includes any condition resulting in admission to intensive care or the use of 4 or more units of packed red blood cells given in cases of bleeding. A second, “expanded” definition of SMM adds criteria including an estimated blood loss of 2 liters or more, unplanned hysterectomy, and readmission to the hospital for specialty services in the first 30 days after delivery.

The researchers found that the rate of SMM in the 4198 deliveries studied was 0.9% (36 cases) using the restricted definition, and 1.2% (52 cases) using the expanded definition. Postpartum readmission to the hospital and blood loss of 2 liters or more accounted for most of the difference. Under both SMM definitions, the majority of the severe complications developed after childbirth and in association with Cesarean delivery, investigators said.

Lead researcher Adi Hirschberg, MD, said the results suggest that the expanded definition of SMM provides a better measure of women at risk and improved all aspects of postpartum care.

The second study examined data from 90 US birth hospitals to see whether higher Maternal Level-of-Care Designations are associated with fewer SMM events in high-risk pregnancies. Sindhu Srinivas, MD, MSCE, said the team wanted to know whether classifying hospitals by care levels will show that patients at hospitals with higher-level designations has better outcomes. They used telephone surveys to collect data from hospitals, and assigned hospital care levels of 1 through 4 based on the proposed criteria. For the approximately 135,000 deliveries covered by the survey, the researchers found that the frequency of SMM was 1.9% overall, but 8.5% for high-risk pregnancies. There were a greater number of high-risk pregnancies at Level-4 hospitals, as expected. Adjusting the data to account for differences in health status among patients at each hospital did not produce any significant association between SMM rates and hospital care levels.

Srinivas concluded that what is needed is a concerted, national effort to improve how we collect this kind of data so that we can evaluate SMM issues better, make a positive impact on maternal care, and reduce morbidity and mortality.