Decoding the link between sickle cell disease and higher death risk in pregnant women

A connection between having sickle cell disease (SCD), a hereditary blood ailment, and having a significantly increased risk of maternal morbidity and mortality, is found. Their analysis, using a large national administrative database with records for pregnant people with SCD, found the maternal mortality rate was 26 times greater than the national average. This figure has not improved since the last time this population was assessed.

In the United States, the condition is most prevalent in the Black community, according to Centers for Disease Control and Prevention. In 2000 to 2003, the maternal mortality rate for people with sickle cell disease was 7.2 deaths per 10,000. In this study looking at data collected 15 years later, the mortality rate among pregnant people with SCD was 13.3 deaths per 10,000. 

In the new study, researchers applied the U.S. Centers for Disease Control and Prevention Severe Maternal Morbidity (SMM) index to the National Inpatient Sample -- a nationally representative sample of hospital admissions in the United States. Their analysis covered information collected from 2012-2018, which included 5,401,899 deliveries.

This figure comprised 3,901 deliveries among pregnant people with SCD and 742,164 deliveries among Black people. Eighty-four percent of those with sickle cell disease who delivered were Black pregnant people. Maternal mortality -- defined as death during pregnancy, at delivery, or soon after delivery -- was highest among those with SCD, at 13.3 per 10,000, compared to 1.2 per 10,000 among pregnant Black people and without SCD and 0.5 per 10,000 among non-Black, non-SCD patients during the study period. 

The researchers noted that despite improvements in the care of people with SCD and improvements in the care of high-risk pregnancies, maternal mortality and morbidity rates of people with SCD have not improved.

These findings suggest that advancements in SCD and high-risk OB care are not reaching enough pregnant people with SCD, the researchers said. In the United States, 90 per cent people with SCD are Black, so pregnancies among people with SCD are often exposed to the harms of systemic and interpersonal racism. These factors contribute to high rates of maternal morbidity and mortality among pregnant Black Americans and, the investigators show, this also affects people with SCD.

"Our work demonstrates that people with sickle cell disease face risk over and above other pregnant people with Black race. Among the risks that are specific to people sickle cell disease are a highly morbid pre-existing condition, a lack of treatment options, in part due to the insufficient research focused on pregnant people with sickle cell disease, and to the absence of high-quality specialty care in many regions of the country," said Macy Early, medical student at Johns Hopkins University School of Medicine. 

About sickle cell disease

SCD is an inherited blood disorder that is estimated to affect 70,000 to 100,000 Americans. The genetic alteration at the root of the disease affects red blood cells that contain hemoglobin, the protein responsible for transporting and delivering oxygen to the body, to become 'sickled' in appearance. The disease not only causes anemia, strokes, organ damage and shortened life spans, but also repeated and frequent episodes of severe pain when the misshapen red blood cells get stuck in small blood vessels. 

Although SCD is a lifelong debilitating illness, advances in treatment have led to nearly all affected people reaching their reproductive years in the United States. As such, there is a growing population of people impacted by the effects of SCD in pregnancy and study of possible treatments is needed. 

For the mother, SCD is linked to heightened risks of blood clots, chronic pain, anemia and preeclampsia (high blood pressure during pregnancy). The researchers confirmed that babies born to people with SCD tend to be smaller than average, delivered early and show damage to the placenta. Data from this study also affirm that SCD is associated with an increased risk of fetal death. 

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