Racial Disparities Persist in Maternal Morbidity, Mortality and Infant Health

June 14, 2020

American women die in childbirth at a higher rate than in any other developed country, while non-Hispanic Black women are more than 3 times more likely to have a maternal death than white women in the United States, according to a review presented at the American Diabetes Association’s 80th Scientific Sessions.

A session held at the American Diabetes Association’s 80th Scientific Sessions highlighted striking racial disparities in maternal mortality, morbidity, and infant health.

American women die in childbirth at a higher rate than in any other developed country, while non-Hispanic Black women are more than 3 times more likely to have a maternal death than white women in the United States, according to a review presented at the meeting.

Pregnancy related mortality can be defined as death of the mother during pregnancy, delivery, or within one year postpartum. While 700 pregnancy-related deaths occur each year, 2/3 of these deaths are considered to be preventable.

Overall pregnancy related mortality in the United States occurs at an average rate of 17.2 deaths per 100,000 live births. However, that number jumps to 43.5/100,000 for non-Hispanic Black women and decreases to 12.7/100,000 for non-Hispanic white women and 11/100,000 for Hispanic women.

For mothers of all backgrounds, leading causes of death include cardiovascular conditions, hemorrhage, and infection. However, for non-Hispanic Black women, leading causes of death include cardiovascular conditions in addition to cardiomyopathy, pre-eclampsia, and eclampsia (hypertensive disorders).

Non-Hispanic Black women are also significantly more likely to have a severe maternal morbidity (SMM) event at the time of delivery. For every maternal death there are 70 cases of SMM events that are considered “near misses.” These events can have long-term or short-term consequences to a woman’s health. Over the past 20 years, cases of SMM have increased by over 200%, while cases disproportionately affect Black women. One study found Black women experienced SMM at a rate 2.1 times greater than that of white women.

To better understand and address these disparities, researchers suggest providers increase screening for social determinants of health. Levels of stress, trauma, food insecurity, neighborhood violence, and access to prenatal care are all factors that may contribute to the disparities and warrant further investigation.

Although most maternal deaths result from cardiovascular and hypertensive disorders, researchers found Asian/Pacific Island women exhibit the highest prevalence of gestational diabetes, which can increase pregnancy complications, at 14.8%.

One study presented in the session focused on behavioral interventions and protective factors among women with gestational diabetes. A Kaiser Permanente analysis of women in northern California found Black women have a lower prevalence of gestational diabetes when compared with Asian Indian, Filipina, Southeast Asian and Chinese women. White women had the lowest rates of the disease overall.

Screening for postpartum diabetes is recommended to all women within 4 to 12 weeks postpartum. However, rates of screening vary among women with different racial and ethnic backgrounds, suggesting tailored strategies to reduce risk and improve healthcare behaviors may be effective.

An additional study explored how racial and ethnic disparities impact severe neonatal morbidities, specifically among very preterm children (born <32 weeks of gestation). Preterm birth has been associated with several health conditions developing later in life, including diabetes.

Presenter Teresa Janevic, PhD, defined race as “linked to phenotype and /or ancestry that indexes one’s location on the US social hierarchy of socially constructed groupings (i.e., races) that has been based primarily on skin color.” In contrast, Janevic defined ethnicity as “tied to race and used both to distinguish diverse populations and to establish personal or group identity, usually based on shared culture or beliefs.”

In a population-based retrospective cohort analysis using hospital discharge data linked with vital statistics at birth and death records, researchers determined Black infants were at the highest risk of dying within less than 28 days after discharge, or suffering neonatal morbidities in the time between birth and discharge. Black infants were followed by Hispanic infants, while white and Asian infants had similar low risks.

Of the 39 New York City hospitals included in the study, researchers found a 6-fold difference in risk of combined mortality and morbidity outcomes. “Black infants were at twice the risk of being at a hospital that has risk-adjusted high rates of combined mortality and morbidity,” Janevic noted, while Hispanic infants had a 1.5 increased risk to receive care from one of these hospitals. “Hospital quality where women of color deliver likely contributes to these disparities,” she concluded.

Another investigation detailed how environmental factors and population level exposures impact disparities in preterm birth and infant mortality. “Non-Hispanic Black infants compared with non-Hispanic white infants have twice the risk of death in the first year,” explained presenter Heather Burris, MD. “This is particularly striking because Black infants just make up 15% of all births in the United States but are counting for 29% of all deaths.”

Among causes of infant death, preterm birth and low birth weight related death, along with pregnancy complications, account for the highest racial and ethnic disparities between non-Hispanic Black and white infants. Black infants are also significantly more likely to be born preterm than white infants.

Researchers note genetics and education level have very little impact in accounting for disparities in preterm birth. Although women with higher education tend to have lower preterm birth rates, Black women who graduated from college have a higher risk of preterm birth than white women who dropped out of high school.

Through analyzing delivery data and creating models based on air pollution severity in Philadelphia, Pennsylvania, investigators discovered air pollution is associated with spontaneous preterm birth. Data also show Black Americans experience consistently higher exposure to air pollutants, measured in fine particulate matter (PM)2.5.

An additional analysis between preterm birth and nationwide neighborhood deprivation index (encompassing income below the poverty level, vacant homes, education levels, among other factors) found that Black women experience neighborhood deprivation exposure at almost 2 standard deviations (SDs) higher than white women in Philadelphia.

Overall, Black women are 4 times more likely to live in a neighborhood with high violent crime and high air pollution than white women. “When we look at preterm birthweights, we can see that it is women living in these high-high neighborhoods that have the highest risk of preterm birth,” Burris said. However, these associations were consistent regardless of race.

Discrimination, resulting in income inequality and residential segregation due to longstanding systemic racism account for these disparities. “Where we live and how much money we make determines our educational level and where we live also determines our toxic environmental exposures. All of this is also associated with psychosocial stress,” said Burris. Both physical and psychological stressors can lead to low birth weight and other health disparities.

“Interrupting preterm health disparities will require a movement. It’s going to require societal interventions to improve environments,” she concluded.