In-Hospital Delivery-Related Maternal Mortality on the Decline

While in-hospital delivery-related maternal mortality has decreased, severe maternal morbidity increased, according to a retrospective cross-sectional study.

Among over 11 million hospital discharges from 2008 to 2021, regression-adjusted maternal mortality per 100,000 discharges decreased from 10.6 deaths in 2008 to 4.6 deaths in 2021, reported Dorothy Fink, MD, of the Department of Health and Human Services in Rockville, Maryland, and colleagues.

Each subsequent year after 2008 had an 11% decrease in odds of death compared with the previous year (adjusted OR 0.89, 95% CI 0.87-0.92), they noted in JAMA Open Network.

"This large national study found a decreasing trend of in-hospital delivery-related maternal mortality during 2008 to 2021, regardless of racial or ethnic group, age, or mode of delivery, likely demonstrating the impact of national and local strategies focused on improving the maternal quality of care provided by hospitals during delivery-related hospitalizations," Fink and team wrote.

The size of the decline in mortality differed across racial groups, ranging from a 92% decrease for American Indians to a 40% decrease in white women.

However, the prevalence of severe maternal morbidity -- defined by the CDC as "unexpected outcomes of labor and delivery that result in significant short- or long-term consequences to a woman's health" -- increased from 146.8 to 179.8 events per 10,000 hospital discharges over this time period.

Fink and colleagues observed the highest overall rates of severe maternal morbidity in Asian, American Indian, and Pacific Islander women. It's estimated that for every pregnancy-related death, an estimated 20 to 30 more women are affected by severe maternal morbidity.

The most common severe morbidity was blood transfusion, with an overall rate of 108.4 per 10,000 discharges. Other relatively common morbidities included disseminated intravascular coagulation (24.7 per 10,000 discharges), hysterectomy (11.0), acute respiratory distress syndrome (9.8), acute kidney failure (9.7), sepsis (7.4), eclampsia (7.2), shock (6.1), and acute heart failure or pulmonary edema (5.6).

The overall maternal mortality rate in the U.S. has risen in recent years, jumping from 20.1 deaths per 100,000 live births in 2020 to 32.9 deaths per 100,000 live births in 2021, according to the CDC, in contrast to the findings on in-hospital births specifically.

"Much of the reporting on maternal mortality has focused on the increasing maternal mortality rates," Fink told MedPage Today in an email. "As a result, this has led many people to believe that hospitals may be the main cause of maternal mortality."

"This study specifically looked at inpatient delivery-related outcomes and found a 57% decrease from 2008-2021," she noted. "The decreasing mortality rates within the inpatient delivery setting demonstrated a statistically significant and a welcome finding for all women."

Risk factors for mortality included advanced maternal age (age 35-44 years vs 25-34 years: aOR 1.49, 95% CI 1.22-1.84), cesarean delivery (aOR 2.28, 95% CI 1.87-2.79), and COVID-19 diagnosis (aOR 13.31, 95% CI 8.95-19.7).

Among the assessed comorbidities and acute complications, cardiac complications, cystic fibrosis, aneurysm, trauma, and puerperal cerebrovascular disorder were all risk factors associated with death during delivery-related hospitalization, Fink and team said.

Risk factors for severe maternal morbidity included ages 24 or younger or ages 35 and older, racial or ethnic minority status, cesarean delivery, Medicaid insurance, and having one or more comorbidities.

"The severe maternal morbidity at the time of delivery increased by 2% annually, with an overall increase of 22% from 2008-2021," Fink said. "Severe maternal morbidity is likely increasing due to the overall health of U.S. women giving birth, including increases in maternal age, obesity, and pre-existing medical conditions."

"While these findings do not have the same level of statistical confidence as identified with mortality, these data do clearly support the importance of the need to address maternal health across the continuum," she added. "All providers, particularly obstetrical providers who are responsible for maternal care, are critical to advancing and sustaining national quality improvement efforts focused on identification and management of conditions impacting maternal health outcomes."

Eileen Wang-Koehler, MD, of the Hospital of the University of Pennsylvania in Philadelphia, told MedPage Today that lower in-hospital delivery mortality rates are a "great sign that public health- and hospital-level strategies to reduce mortality are working."

This study used data from the Premier PINC AI Healthcare Database, a large, geographically diverse, all-payer hospital administrative database, from January 2008 to December 2021. They included 11,628,438 delivery-related hospital discharges.

Mean age of patients was 28, 53.3% were white, 15.2% were Hispanic, and 14.1% were Black. Medicaid was the primary insurance payer for 42.6% of patients, and 50.1% had commercial insurance. About 67% of the cohort gave birth vaginally.

Fink and co-authors noted that some variables may have been misclassified due to hospital procedure coding inaccuracies in the database. Deaths before admission or after hospital discharge were not included in the study, and pre-admission comorbid conditions may have been omitted.

Wang-Koehler added that the findings are "limited to the delivery period, and they do not capture data around the postpartum period where we know that maternal mortality and morbidity is high -- and maybe we aren't doing as good of a job in that period to prevent mortality as we are during the delivery."

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