June/July 2022 Issue
Hypertensive Disorders and Kidney Disease in Pregnancy
By Carrie Dennett, MPH, RDN, CD
Vol. 24, No. 5, P. 28
A recent study shows glaring racial disparities regarding these complications. Today’s Dietitian explores the research and the underlying factors driving inequities and offers strategies for counseling patients.
Up to 1 in 10 pregnant women are affected by hypertensive disorders of pregnancy (HDP), including chronic hypertension, gestational hypertension, preeclampsia, and eclampsia.
Hypertension that occurs prepregnancy or earlier than 20 weeks into a pregnancy is simply classified as chronic hypertension, but these women can develop superimposed preeclampsia if they experience symptoms such as higher blood pressure during pregnancy.1 Gestational hypertension is blood pressure of 140/90 mm Hg or higher after 20 weeks of gestation in women with previously normal blood pressure.2 Preeclampsia is a pregnancy disorder associated with new-onset hypertension and is most common in the second half of pregnancy—often near the end—but can happen in the days or weeks after childbirth. It’s accompanied by new-onset proteinuria (ie, increased levels of protein in the urine) and/or organ dysfunction.3 Eclampsia is a complication of preeclampsia in which the patient develops seizures. The majority of cases occur after 28 weeks of pregnancy but can happen during delivery or up to six weeks postpartum.4
It’s estimated that more than 15% of women are affected by HDP during one or more pregnancies. HDP is a major cause of maternal death globally2 and is associated with greater risk of pregnancy complications such as preterm delivery, low-birthweight infants, placental abruption, and pregnancy loss.
Moreover, research has long established that HDP can increase a woman’s risk of developing long-term CVD, but what’s less known is that HDP increases a woman’s risk of developing long-term kidney disease, especially end-stage kidney disease.5
A retrospective cohort study published earlier this year in the journal Hypertension—using the records of 391,838 women aged 12 to 49 who had a live birth in South Carolina between 2004 and 2016—looked at the relationship between HDP and postpartum onset of kidney disease. Unlike previous studies looking at the same associations, this study included both non-Hispanic white and non-Hispanic Black women and also assessed the impact of prepregnancy hypertension.6
“While there have been past studies on hypertensive disorders of pregnancy and kidney disease in relation to maternal outcomes following pregnancy, most studies did not have the diverse population that would allow them to evaluate race,” says Dulaney Wilson, PhD, an assistant professor in the department of public health sciences at Medical University of South Carolina and one of the study’s authors.
Wilson says that while the relationship between hypertension and kidney disease is well researched, few studies focus on pregnancy for what she suspects are a few reasons. One is the perception that HDP are a short-term problem that will get better after delivery. Two other reasons are that relatively few pregnant women go on to develop kidney disease, and it’s difficult to show causation when there’s a long latency period between exposure and outcome.
Almost 65% of the women in the study were white, and just over 35% were Black. A relative few (0.4%) had prepregnancy hypertension, but 16.3% had HDP and 2.5% had both. The authors observed what they called “stark differences” in how many Black women developed kidney disease compared with white women, as illustrated by the following findings:
• Compared with having neither condition, Black women with both conditions had a 3.88-fold chance of developing kidney disease within five years of giving birth and a three-fold risk of developing it within 14 years. Among Black women with only HDP, the risk of developing kidney disease was 2.3-fold higher within five years of delivery and 1.96-fold higher within 14 years.
• Compared with white women with neither condition, white women with both conditions experienced a 1.86-fold higher risk of developing kidney disease within five years of delivery and a 1.97-fold higher risk within 14 years. Among white women with HDP, the risk was 1.97-fold higher within five years of delivery and 1.7-fold higher within 14 years.
While the researchers expected the risk of maternal kidney disease to be higher in Black women with HDP or prepregnancy hypertension, given their higher rates of hypertension generally, “it was somewhat surprising to see the magnitude of the differences between non-Hispanic Black and non-Hispanic white women with the same exposures after accounting for characteristics such as age, income, smoking, BMI, and clinical comorbidities,” Wilson says.
A systematic review and meta-analysis of 23 studies published in the Journal of the American Medical Association in 2020 found that the risk of end-stage kidney disease was 4.9 times higher in women who had preeclampsia and 3.6 times higher in women who had gestational hypertension, compared with women who had normal blood pressure during pregnancy. The authors concluded that it’s unclear whether HDP unmasks an existing predisposition to kidney disease or if it causes endothelial or organ damage that increases the risk of developing kidney disease. Either way, they say the health care system needs to provide long-term follow-up of women with HDP and offer appropriate preventive care to help reduce their risk of developing clinically significant kidney disease.5
Causes of Disparities
The 2017 ProPublica-NPR maternal health investigative series “Lost Mothers” called attention to the fact that the United States has the highest rate of maternal deaths in the developed world. Some of the underlying reasons for this rate also contribute to nonfatal pregnancy complications, including HDP. Many women are delaying having children, so new mothers are older than they used to be and more likely to already have complex medical histories that may not be addressed before conception, as one-half of US pregnancies are unplanned. Plus, even with good health insurance, new mothers may not get the care they need because of a fragmented health care system that emphasizes the health of the infant over the health of the mother.7
Unfortunately, HDP and other adverse pregnancy outcomes typically are the concern of obstetricians only. Not only may obstetric health records be separate from general health records, but primary care physicians may not fully understand the impact of HDP on health further down the road, and patients who experienced HDP are unlikely to know it may increase their future CVD or kidney disease risks.3
Esther Tambe, MS, RD, CDN, CDCES, owner of Esther Tambe Nutrition in Long Island, New York, notes that in the South Carolina study, more than one-half of the women were on Medicaid. “Whether it be maternal health, kidney heath, diabetes, or cancer, access to care is not the same when it comes to insurance and what providers you have access to. Not all providers accept Medicaid.” She says racial differences in maternal health outcomes largely come down to poor access to quality health care and systemic racism.
A 2022 American Heart Association scientific statement on hypertension in pregnancy called racial maternal health disparities in the United States “unacceptably large,” adding that “in addition to Black, American Indian, and Alaska Native women having poorer social determinants of health, implicit racial bias is present within the US health care system and management of severe maternal morbidity is consistently worse for these women.”2 A 2022 American Heart Association Presidential Advisory called structural racism a fundamental driver of health disparities, stating that “higher socioeconomic status does not protect Black people from the impact of structural racism and its health effects.”8
Whitney Trotter, MS, RDN, LDN, RN, RYT, an antiracism educator and consultant and founder of Bluff City Health in Memphis, says this is a topic practitioners need to discuss more in dietetics and health care. “How do we have these conversations in a more open space, because I believe systemic racism is a public health issue,” she says.
In addition to creating inequities in health care access and quality of care, racism can take a direct physical toll by causing chronic and excessive activation of the body’s stress response system, which can lead to greater allostatic load, or long-lasting and cumulative damage to the body and brain. The weathering hypothesis uses measures of allostatic load to explain the effect of race-based socioeconomic disadvantage on deteriorating health in early adulthood among Black populations—a deterioration that accumulates to produce greater racial health inequalities with age.9
The term “weathering” came from public health researcher Arline Geronimus in the 1970s, who observed that white women in their 20s were more likely to give birth to a healthy baby than those in their teens, but the reverse was true for Black women. Her subsequent research suggested that Black women were less healthy at age 25 than they were at 17.10,11 Trotter says she’s observed this phenomenon in Memphis, which has a high infant mortality rate among Black mothers who are college age and older, while Black teenage mothers with little to no access to health care fare better.
Access to health care is itself a complicated, multifactorial issue. “How many Black moms have access to transportation? If they’re essential workers, are they able to get to appointments?” Trotter asks. “When you think about Black maternal health, and you think about the father of OB/GYN [J. Marion Simms] operating on black women without anesthesia,12 and you think about Henrietta Lacks [a young Black mother whose cervical cancer cells were used in research without her knowledge or consent],13 there’s always been this idea about Black women and perinatal health that they’re disposable,” Trotter says, also pointing to research showing that Black patients are less likely to be treated appropriately for pain, in part due to the false belief that Black people literally have thicker skin than white people and experience less pain.14
Tambe used to work in dialysis, providing care to a diverse and in some cases underserved population. She says not all populations received the same quality of education and that she saw a lot of fear being instilled into patients. “Scaring people doesn’t do it, and it takes away trust in the provider,” she says. “A lot of Black patients have this medical distrust already due to history.” She says she observed many patients being labeled as “noncompliant” without the provider understanding why—“Are they noncompliant or nonadherent, or is something else going on?”—and a lot of shame and scolding, including report cards that had a smiley face or an unhappy face. “Think of the trauma that can cause. Imagine someone coming out in a white lab coat with those report cards,” she says.
Possible Solutions in Health Care and Dietetics
One way to start addressing health inequities and the needs of diverse populations—in health care and dietetics—is through a more diverse provider population, along with cultural competency and humility. To that end, the Academy of Nutrition and Dietetics’ Inclusion, Diversity, Equity and Access Action Plan has been designed to increase inclusivity in the dietetics profession. Diversify Dietetics, founded by Oakland, California–based dietitian Deanna Belleny Lewis, MPH, RDN, and Atlanta-based dietitian Tamara Melton, MS, RDN, has the mission of empowering nutrition leaders of color to increase racial and ethnic diversity in the field of nutrition, reflecting the diverse communities the profession serves.
“I think diversity is great, but I really want dietetics to move more towards equity and justice. And when you talk about cultural humility and cultural competency, it can’t just be to check the box,” Trotter says, adding that Memphis is racially diverse, but even at the University of Memphis cultural competency is a to-do. “We really don’t understand epigenetics and historical trauma and how that plays out, and the majority of people who can diagnose and prescribe are white.”
Trotter says dietitians need to ask whether the most marginalized people can access care, and she feels there isn’t enough attention paid to intersectionality, a concept introduced in 1989 by law professor Kimberlé Crenshaw, JD, LLM, a professor of law at Columbia Law School and the University of California, Los Angeles, to denote the way race and gender interact to shape Black women’s experiences.15 Intersectionality has since become used to explore how various systems of inequality based on gender, race, ethnicity, sexual orientation, gender identity, disability, class, and other forms of discrimination intersect to create unique effects.16 “I want to see that really fleshed out in dietetics,” she says.
Tambe says diversifying the field is also important. “It should be a mission to increase racial and ethnic diversity in the field of dietetics,” she says. “That allows patients to feel safe, because the people who are caring for them look like them and understand them, so they’re more likely to open up to them. Everyone can do the work and learn about things, and that’s so important, but if we can bring in more people who look like our clients, that’s better.”
She adds that while there’s more representation of diverse groups in dietetics, there’s not enough support for that representation. Tambe also says current and prospective dietitians need to do better at checking their biases. “There are a lot of microaggressions that happen during internships that can put someone off continuing,” she notes.
Recommendations for RDs
The dietitian’s role in helping to prevent HDP—and later in life adverse health outcomes—can begin before conception. RDs can counsel young women who plan to have children on eating to support healthy blood pressure now—especially if they have a personal or family history of hypertension, CVD, or kidney disease. Epidemiologic cohort studies suggest that healthful dietary patterns—high intake of fruits, vegetables, legumes, nuts, and fish, and low intake of red and processed meats—up to three years before pregnancy are associated with lower risks of HDP.3
“I always start with asking what food the person has access to, and go from there,” Trotter says. “I always ask about accessibility.” In the postpartum period, she says dietitians should look beyond the nuts and bolts of nutrition to factors like stress levels and social determinants of health. “That postpartum period is so significant,” she says. “Does she have a partner who’s going to be able to help? When is she going to have to go back to work? Has she experienced trauma to her body, and how does that impact her desire and ability to breast-feed?”
Regarding women who are between pregnancies or well past their most recent pregnancy, dietitians can ask about adverse pregnancy outcomes. If the dietitian has access to the patient’s EHR, they can review any pregnancy-related records.
Tambe says it’s important for dietitians to understand the cultures of the patients with whom they work. “Go out,” she says. “Learn [about] the neighborhood you’re in. Not just by reading a book, but by going out in the community. Where do they shop? You can ask them what they eat.” She recalls shadowing a dietitian who asked a Black patient from West Africa if he was eating egg whites for breakfast. He says he was, but when the dietitian left, Tambe asked the patient what he really ate for breakfast, because she knew that it was typical in his culture to eat leftovers for breakfast. She says it’s helpful to ask questions beyond just doing a food recall. “We don’t always have to be the one doing the educating,” she says. “We can learn from our clients. I think it’s OK to be human. We can ask them, ‘How’s your day? How are you feeling today?’ We can look for those nonverbal cues that they’re apprehensive. We can’t be by the book all the time. If you’re not crossing someone’s boundaries, it’s OK to ask them questions and learn from them.”
— Carrie Dennett, MPH, RDN, CD, is the nutrition columnist for The Seattle Times, owner of Nutrition by Carrie, and author of Healthy for Your Life: A Holistic Guide to Optimal Wellness.
1. Seely EW, Ecker J. Chronic hypertension in pregnancy. Circulation. 2014;129(11):1254-1261.
2. Garovic VD, Dechend R, Easterling T, et al. Hypertension in pregnancy: diagnosis, blood pressure goals, and pharmacotherapy: a scientific statement from the American Heart Association. Hypertension. 2022;79(2):e21-e41.
3. Parikh NI, Gonzalez JM, Anderson CAM, et al. Adverse pregnancy outcomes and cardiovascular disease risk: unique opportunities for cardiovascular disease prevention in women: a scientific statement from the American Heart Association. Circulation. 2021;143(18):e902-e916.
4. Magley M, Hinson MR. Eclampsia. Treasure Island, FL: StatPearls Publishing; 2022.
5. Barrett PM, McCarthy FP, Kublickiene K, et al. Adverse pregnancy outcomes and long-term maternal kidney disease: a systematic review and meta-analysis. JAMA Netw Open. 2020;3(2):e1920964.
6. Malek AM, Hunt KJ, Turan TN, et al. Hypertensive disorders of pregnancy with and without prepregnancy hypertension are associated with incident maternal kidney disease subsequent to delivery. Hypertension. 2022;79(4):844-854.
7. Churchwell K, Elkind MSV, Benjamin RM, et al. Call to action: structural racism as a fundamental driver of health disparities: a presidential advisory from the American Heart Association. Circulation. 2020;142(24):e454-e468.
8. Geronimus AT, Hicken M, Keene D, Bound J. "Weathering" and age patterns of allostatic load scores among blacks and whites in the United States. Am J Public Health. 2006;96(5):826-833.
9. Geronimus AT. The weathering hypothesis and the health of African-American women and infants: evidence and speculations. Ethn Dis. 1992;2(3):207-221.
10. Geronimus AT. Black/white differences in the relationship of maternal age to birthweight: a population-based test of the weathering hypothesis. Soc Sci Med. 1996;42(4):589-597.
11. Prather C, Fuller TR, Jeffries WL 4th, et al. Racism, African American women, and their sexual and reproductive health: a review of historical and contemporary evidence and implications for health equity. Health Equity. 2018;2(1):249-259.
12. Henrietta Lacks: science must right a historical wrong. Nature. 2020;585(7823):7.
13. Hoffman KM, Trawalter S, Axt JR, Oliver MN. Racial bias in pain assessment and treatment recommendations, and false beliefs about biological differences between blacks and whites. Proc Natl Acad Sci USA. 2016;113(16):4296-4301.
14. Martin N. Lost mothers: maternal care and preventable deaths. ProPublica website. https://www.propublica.org/series/lost-mothers
15. Crenshaw K. Mapping the margins: intersectionality, identity politics and violence against women of color. Stan L Rev. 1990;43(6):1241-1299.
16. What is intersectionality? Center for Intersectional Justice website. https://www.intersectionaljustice.org/what-is-intersectionality