AJOG: Pregnancy-Related Deaths Due to Hemorrhage: Pregnancy Mortality Surveillance System, 2012–2019

ABSTRACT:

Hemorrhage has been a leading cause of pregnancy-related death in the Centers for Disease Control and Prevention Pregnancy Mortality Surveillance System since 1987 when reporting began. Pregnancy Mortality Surveillance System data from 2012 to 2019 were analyzed to describe pregnancy-related deaths from hemorrhage. Pregnancy-related mortality ratios were estimated for hemorrhage overall and by hemorrhage subclassifications. Specific subclassifications of hemorrhage-related deaths were analyzed by sociodemographic characteristics. Overall, there were 606 deaths due to hemorrhage. The pregnancy-related mortality ratio for hemorrhage overall was 1.94 per 100,000 live births. Ruptured ectopic pregnancy was the most frequent subclassification (22.9%) of pregnancy-related hemorrhage deaths, followed by postpartum hemorrhage (21.2%). There were no significant trends in the pregnancy-related mortality ratio, overall or among any subclassification of hemorrhage deaths, from 2012 to 2019. Reporting subclassifications of pregnancy-related hemorrhage deaths could improve the ability to focus interventions and assess progress over time.

Hemorrhage has been identified as one of the most frequent Pregnancy Mortality Surveillance System–identified underlying causes of death since reporting began in 1987,¹ accounting for 12.1% of deaths from 2017 to 2019.² Most pregnancy-related deaths with hemorrhage as an underlying cause of death are preventable.³ The objective of this project was to provide additional details on pregnancy-related deaths for which hemorrhage was the Pregnancy Mortality Surveillance System–identified underlying cause of death in the United States from 2012 to 2019.

METHODS

All cases of pregnancy-related death with an underlying cause of hemorrhage were identified in the Pregnancy Mortality Surveillance System. This study did not involve human subjects as defined in 45CFR 46.102(e) and thus did not require IRB review. Pregnancy Mortality Surveillance System methodology has been described previously.¹ Briefly, the Centers for Disease Control and Prevention Division of Reproductive Health requests that all states, the District of Columbia, and New York City voluntarily send death records, linked live birth or fetal death records if applicable, and additional data when available on deaths that occurred during pregnancy or within 1 year after the end of pregnancy. Information on individual deaths is reviewed by medically trained epidemiologists to determine pregnancy relatedness and cause.¹ A death is determined to be pregnancy related if the death was caused by a pregnancy complication, a chain of events initiated by pregnancy, or the aggravation of an unrelated condition by the physiologic effects of pregnancy. Underlying cause of death is classified into 10 mutually exclusive classifications, including hemorrhage.² A more specific subclassification of the underlying cause of death, within the 10 higher-level classifications, is then assigned to each death. Race and ethnicity data are collected in the Pregnancy Mortality Surveillance System to describe known differences. These data are from matched live birth or fetal death record or, if those records were unavailable, from death records.

We aggregated Pregnancy Mortality Surveillance System data for the years 2012–2019. Pregnancy-related mortality ratios (number of pregnancy-related deaths per 100,000 live births) with 95% CIs were calculated overall and for each hemorrhage subclassification (ectopic pregnancy, postpartum hemorrhage, placenta accreta spectrum, abruption, previa, uterine rupture, other, unknown) over the 8-year study period in 2-year intervals. The number of live births was obtained from U.S. natality files from the National Vital Statistics System. SAS 9.4 was used for all analyses.

RESULTS

Overall, 5,309 pregnancy-related deaths were identified. Among these, 606 (11.4%) were determined to have hemorrhage as an underlying cause. The overall pregnancy-related mortality ratio for the period was 17.0, and the pregnancy-related mortality ratio for hemorrhage deaths was 1.94 per 100,000 live births (Table 1). Ruptured ectopic pregnancy was the most frequent cause of hemorrhage-related mortality (22.9%), followed by postpartum hemorrhage (21.2%) and placenta accreta spectrum (12.7%). The most frequent hemorrhage subclassification varied by race and ethnicity. Placenta accreta spectrum was the most frequent (20.6%) among Hispanic deaths, postpartum hemorrhage among non-Hispanic Asian deaths (37.8%), and ruptured ectopic pregnancy among non-Hispanic Black (32.6%) and non-Hispanic White deaths (23.4%).