Maternal cardiac arrest more common than originally thought

The proportion of women who have cardiac arrest while in the hospital to give birth is much higher than previously believed, based on an analysis of 13 years of data published in the April issue of Anesthesiology. While still a rare occurrence, the research found that 1 in 12,000 pregnant women hospitalized for delivery experience cardiac arrest. Most women survive, and survival is increasing over time.  

“The frequency of maternal cardiopulmonary arrest in the United States is unknown, and there are limited population-level data to inform guideline development or systems preparations for these rare emergencies,” explained the authors, led by Jill M. Mhyre, MD, of the University of Arkansas for Medical Sciences in Little Rock.

They analyzed data from the Nationwide Inpatient Sample (NIS) between 1998 and 2011 to determine how many women experienced cardiac arrest while in the hospital to give birth. The NIS contains data on more than 56 million hospitalizations for delivery. They also assessed the relationship between maternal cardiac arrest and obstetric procedures, hospital delivery volume, and demographic and socioeconomic characteristics.

One in 12,000 (or 8.5 per 100,000) hospitalizations for delivery involved a maternal cardiac arrest. The most common potential causes were hemorrhage, heart failure, amniotic fluid embolism and sepsis.

About 60 percent survived to discharge, and survival increased over the data analysis period. Survival depended on the cause of the maternal arrest, and was lowest for aortic dissection or rupture and trauma. Survival was highest for aspiration pneumonitis and complications related to medications.

Women who experienced cardiac arrest were more likely to be non-Hispanic blacks, age 35 or older and covered by Medicaid. Women hospitalized in facilities with more than 1,000 deliveries per year were also more likely to experience cardiac arrest compared with smaller volume facilities. These differences were no longer significant after adjustment for maternal demographics, comorbidities and obstetric conditions.

"A 60 percent rate of survival from cardiac arrest is good, but maternal mortality in the United States remains unacceptably high," Mhyre said in a press release. "This information will assist healthcare providers to deliver the most effective maternal cardiopulmonary resuscitation (CPR) when both the mother's and baby's lives are on the line."