OPINION: Pregnancy and Preeclampsia: A Dangerously Disproportionate Risk for Black Women

This past January, Dr. Janell Green Smith, certified nurse-midwife and maternal health advocate, died at 31 years of age from childbirth-related issues. Dr. Green Smith was admitted to the hospital because of severe preeclampsia, a pregnancy-related blood pressure disorder that can cause organ damage and be fatal to both mom and baby. She gave birth via cesarean section to her daughter in late December, but less than a week later, she passed away from postoperative complications.

Preeclampsia is not uncommon. Globally, preeclampsia is responsible for more than 70,000 maternal deaths and 500,000 fetal deaths each year. In the United States, Black women like Dr. Green Smith are 1.5 to 2 times more likely to suffer from the disease than their white counterparts. Beyond tragedy, Dr. Green Smith’s death highlights the real impact of racial disparities in maternal health.

Why didn't I know that U.S.-born Black women face a higher risk of preeclampsia than any other group?

Dr. Green Smith’s story makes me think about my own aunt, who was hospitalized last May due to preeclampsia during her pregnancy with twins. For roughly 200,000 families in America each year, preeclampsia is personal.

Preeclampsia is a pregnancy complication that is characterized by high blood pressure and kidney and liver damage. It is the second leading cause of mortality (death) and morbidity (poor health) in pregnancy globally. While Black people suffer from preeclampsia at a disproportionate rate, preeclampsia is fairly common, affecting 5 to 8% of U.S. pregnancies. The prevalence of preeclampsia is increasing; incidences nearly doubled between 2007 and 2019. These statistics reflect a need to not only improve maternal health for Black Americans but for every American.

I believe improving the birthing outcomes of Black mothers will improve birthing outcomes for every mother.

To better understand preeclampsia, I spoke with Dr. Mancy Tong, a researcher and assistant professor of obstetrics, gynecology, and reproductive sciences at Yale School of Medicine. She explained that preeclampsia is caused when placental cells called extravillous trophoblasts (EVTs) fail to migrate into the uterus. Under normal conditions, EVTs move from the placenta into the uterus to remodel maternal spiral arteries, helping these arteries to widen and allow more blood to flow from the uterus to the placenta as a pregnancy progresses. When EVTs do not properly invade the uterus during preeclampsia, the placenta receives limited blood flow and oxygen.

Preeclampsia is diagnosed after 20 weeks gestation, when the placenta has grown too large for the insufficient blood flow to support it. As a result, the placenta releases stress signals that affect endothelial cells, the cells that line the mother’s blood vessels, and immune cells, which increase inflammation in the mother’s body.

Dr. Tong explained that people often “think of preeclampsia as purely hypertension, but it really isn't. The step that leads to hypertension in preeclampsia is the global endothelial cell dysfunction…Endothelial cells extend into all of the different organs that have microvessels,” including the kidneys, liver, and brain. Rather than merely high blood pressure, preeclampsia is a disease that systemically affects and damages the whole body.

Currently, the only cure for preeclampsia is to deliver the placenta – and the baby. This often leads to pre-term delivery, which brings its own set of health risks and complications.

The exact cause of developing defective EVTs is unknown. Researchers speculate that the mother’s immune system as well as genetics may be involved. The emerging research is promising, yet there is more information available about its risk factors than its causes. A woman is at a higher risk for developing preeclampsia if she is pregnant for the first time, carrying more than one fetus, over 40 years old, obese, or experiences preexisting diabetes and high blood pressure.

Another significant risk factor, statistically, is being African-American.

My Auntie Elizabeth shared with me her journey with preeclampsia during her twin pregnancy last year. Her Ob/Gyn had told her early in the pregnancy that she had expected her to develop preeclampsia due to specific risk factors: It was her first pregnancy, she was carrying multiples, and she was Black.

“I didn’t really accept that in my mind,” my aunt asserted as she reflected on her experience. “I had no symptoms, I had no headache, I had no swelling anywhere.” Despite this, she was having frequent checkups and blood draws multiple times a week due to other factors in her pregnancy. Her bloodwork began to show that her liver function test results were increasing outside of normal range. “There’s nothing in my baseline health that would have caused that.”

In the fifth month of her pregnancy, Auntie Elizabeth was hospitalized. “I went to my appointment and my systolic [blood pressure] was above 180. They urged me to go straight from the office to the hospital. I didn’t leave until I gave birth.” Her doctors gave her antihypertensive medication and constantly monitored her progress and symptoms. Auntie Elizabeth was in-patient at the hospital for about a month, until she gave birth pre-term to her twins.

Studies suggest that racial disparities in preeclampsia are not due to biological factors but rather environmental ones. Researchers at Johns Hopkins found that Black women who were born outside of the U.S. and have lived in the U.S. for less than 10 years show a 26% decreased rate of developing preeclampsia compared to Black women born in the U.S. Meanwhile, white women born in the U.S. had lower preeclampsia rates (7.1%) compared with their foreign-born counterparts. These data suggest that the environment in the U.S. specifically increases preeclampsia risk for people of African descent.

Throughout studies I reviewed, a suggested reason that U.S.-born Black women face higher rates of preeclampsia is a concept called weathering. Weathering is a hypothesis that was suggested by A. T. Geronimus in 1992, that the health of Black women may deteriorate in early adulthood due to prolonged exposure to the stress and other consequences of racism. The weathering hypothesis is supported by the fact that Black women are not protected from preeclampsia by higher levels of socioeconomic status the same way that Hispanic and white women are, signaling that preeclampsia disparities are not only an issue of socioeconomic status.

Dr. Tong states that there is insufficient scientific research that explains how stress might affect preeclampsia. “There are certainly mechanistic connections that can be made [between stress and preeclampsia],” she reasons, “but the current evidence isn’t so strong.”

While more research is needed to explain how stress plays a role in developing preeclampsia, there is evidence that shows high stress over the mother’s lifetime is correlated with increased risk of preeclampsia.

Another theory for the disproportionate rate of preeclampsia in Black women is that there is a higher rate of chronic high blood pressure among the Black female population compared to other groups. Chronic hypertension before pregnancy is a risk factor for preeclampsia, so this could be a contributing factor to higher rates of preeclampsia among Black women. This theory aligns with the weathering hypothesis, as racial discrimination has been associated with increased risk of chronic high blood pressure. In addition to high blood pressure, Black women are affected more by risk factors such as lower socioeconomic status, unequal access to prenatal healthcare, and obesity.

When I asked my Auntie Elizabeth to describe how her life changed after her preeclampsia diagnosis, she expressed that she needed help with things that she normally did not struggle with, and she felt extremely fatigued. She remarked that the hospitalization forced her to slow down, which was particularly new to her.

“Around the time I got my diagnosis and my blood pressure started rising, that’s when my pregnancy really felt like my body was unable to carry it almost…I could not function for myself…I did not have what it took to live my life,” she explained. “I have been hyper independent my whole life. This was the first time that something made me sit all the way down…Psychologically, it opened my eyes to how much I am overfunctioning at baseline.”

She also commented on how tricky it can be for pregnant women with preeclampsia to find emotional support. “It’s pretty isolating. Most of my friends are not moms. When I think about who I went to for support, to be honest with you, I don’t think I was processing any information at all. I was just using everything in my system to exist.”

When considering preeclampsia rates for Black women, she reflected, “Why are the statistics for Black women who go through childbirth so much worse? How much of this is racism? I wonder who’s going to have the courage to answer.”

Despite not having much time or energy to fully process her experience, my aunt understands the heaviness of her journey and that of hundreds of thousands of other women who face preeclampsia each year. “Looking back, it’s pretty scary,” she expressed. “It was really a precarious situation…I’m lucky that I didn’t actually develop anything else.”

All things considered, my Auntie Elizabeth had a good outcome. I am deeply grateful that she and my twin cousins are healthy and thriving. Yet, the statistics show that not every mother with preeclampsia has such positive health outcomes. Over 1,000 women in the U.S. die each year from preeclampsia, and its incidence is on the rise. There also continues to be a stark racial inequality regarding its prevalence, with Black women at a 60% increased risk compared to white women. Some studies have shown that this disparity is also worsening.

Even once a woman gives birth and her preeclampsia resolves, there may be later-in-life complications associated with her preeclampsia that can manifest up to 15 years after birth. The chance of having preeclampsia in a subsequent pregnancy is 20%, but this percentage varies depending on a person’s risk factors. Because of this chance, more than 1 in 4 preeclampsia survivors decide not to have another pregnancy. Additionally, women who have had preeclampsia have an increased likelihood of chronic high blood pressure, stroke, heart disease, and death from cardiovascular events. One study showed that over half of women who had preeclampsia have high blood pressure at the 10-year mark after delivery.

Dr. Tong explains, “what is still debated is whether preeclampsia leads to… all of these diseases or whether preeclampsia is kind of an early cardiovascular stress test.” Researchers are unsure of whether preeclampsia causes these adverse outcomes or simply predicts it.

Racial disparities continue to persist in the long-term effects of preeclampsia. Black women diagnosed with preeclampsia have lower rates of postpartum follow up than women of other racial or ethnic groups. Lack of continuity of care can be catastrophic, especially because of the fatal cardiovascular diseases that are associated with a history of preeclampsia.

There is not yet full scientific understanding on the development of preeclampsia and its long term effects. Additionally, there are limited studies that examine the cause of disparities between racial groups. Echoing my aunt’s sentiment, it is critical that researchers explore these unknowns and strive toward achieving health equity.

Dr. Green Smith will be remembered as a leader in Black maternal mortality; she became a midwife “to be a part of the solution.” Her life and death drive my passion to raise awareness about preeclampsia and disparities in maternal-fetal health. More comprehensive research must be done to close the racial gap in preeclampsia outcomes for Black women like Dr. Green Smith, Auntie Elizabeth, me, and millions more.