Maternal deaths caused by chronic hypertension ‘deserve urgent public health attention’
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Chronic hypertension is a substantial contributor to maternal deaths in the United States, with particular risk among Black women, according to a study published in Hypertension.
After analyzing data from more than 155 million births and 3,287 maternal deaths related to hypertension among women aged 15 to 49 years between 1979 and 2018, the researchers found a 15-fold increase in maternal mortality rates associated with chronic hypertension over the 40-year period.
“Overall hypertension-associated deaths declined in the U.S. over the last 40 years, but this decline is restricted to women who have preeclampsia/eclampsia as the cause,” author Cande V. Ananth, PhD, MPH, MSc, professor, vice chair and chief of the division of epidemiology and biostatistics in the department of obstetrics, gynecology and reproductive sciences at Rutgers Robert Wood Johnson Medical School in New Brunswick, New Jersey, said in a press release.
“If you isolate the data on women who have chronic hypertension, which is defined as a preexisting hypertensive condition of hypertension diagnosed within the first 20 weeks of pregnancy, as a cause, mortality rates have increased quite substantially — on average, by about 9.2% per year over the last 40 years. So, it is the chronic hypertension that has really driven the maternal mortality trends in the U.S. over the last 40 years,” Ananth continued.
The incidence of hypertension-related maternal deaths sharply increased with maternal age, being highest among women aged 45 to 49 years, and obesity, the researchers said. Ananth also noted a substantial race disparity.
“Black women were at anywhere from three- to fourfold increased risk for dying from a hypertension-related cause compared to white women in the United States, and this disparity has persisted for the last 40 years,” Ananth explained, adding that problems with access to care and many risk factors for hypertensive complications are higher among Black women than white women, contributing to this disparity.
The researchers said that strategies are needed to improve areas such as advanced maternal age, obesity and racial inequities in care, which deserve urgent public health attention.
Also, the researchers said their findings underscore the need to better identify and treat women with chronic hypertension and develop targeted prenatal interventions, including tight blood pressure control and efforts to reduce BMI.
“We have gotten much better at treating women with preeclampsia/eclampsia during pregnancy, which has undoubtedly contributed to the decline in maternal death rates, but we haven’t done as good a job in treating women with chronic hypertension,” said Ananth.
“Part of that is because many of these women come in undiagnosed, and it’s often problematic to treat women with drugs to reduce their blood pressure, particularly early in pregnancy, so there’s a conflict of what’s the right approach,” he said.
But focusing on lifestyle choices such as smoking, alcohol consumption, weight and diet both before and early in pregnancy also might reduce hypertensive complications, Ananth added.
The study’s findings have implications for clinical providers as well, Ananth continued, as the burden of maternal deaths occurs within the first 6 weeks after pregnancy.
Approximately 80% to 85% of women with preeclampsia or eclampsia during pregnancy see those symptoms resolve after the placenta is delivered, Ananth said, but the remainder of those women see hypertension persist for the rest of their lives.
“These women are particularly vulnerable and high risk and need to be monitored carefully and treated for hypertensive conditions, particularly through medication and changes in lifestyle/behavior,” he said.