Study finds 15-fold increase in maternal deaths related to chronic hypertension

Increasing numbers of deaths are occurring among women entering pregnancy with pre-existing chronic hypertension, and the trend may be continuing. And Canadian doctors warn there are gaps in awareness and care when it comes to maternal cardiovascular disease (CVD). “The sad truth is that in Canada, and indeed throughout the world, there are large variations in CVD preventative care for women due to a lack of awareness about CVD risks, and sex-specific risk factors,” said Dr. Sharon Mulvagh, a spokesperson for the Canadian Cardiovascular Society. She is also a professor of medicine and co-director of the Women’s Heart Health Clinic at Dalhousie University. A study in Hypertension (Dr. Mulvagh was not part of this) found that over the last four decades in the U.S. maternal deaths due to chronic hypertension increased, even though deaths due to preeclampsia and eclampsia decreased. “In the United States, about 8% to 10% of all pregnancies are complicated by some form of hypertension, with severe preeclampsia and chronic hypertension showing a steady temporal increase over the last 4 decades,” the study said. Read: Women with vascular issues at higher risk of cognitive decline than men The population-based epidemiological study used mortality, age and race data assembled by the National Center for Health Statistics (NCHS) from 50 states and Washington, DC. Researchers focused on women aged 15 to 49 years who had pregnancy and childbirth related deaths from 1979 to 2018. Other data were attained from the death certificates and researchers extracted information about deaths that had hypertensive conditions—specifically chronic hypertension, gestational hypertension, preeclampsia and eclampsia. During the 40-year period there were 155,710,441 live births and 3,287 hypertension-related maternal deaths. They observed a 15-fold increase in maternal mortality rates associated with chronic hypertension. “Overall hypertension-associated deaths declined, but this decline was restricted to women who had preeclampsia or eclampsia as the cause. But if you isolate the data on women who had chronic hypertension, mortality rates increased substantially,” said lead author Cande Ananth, professor of epidemiology and obstetrics, gynecology and reproductive sciences at Rutgers Robert Wood Johnson Medical School. Chronic hypertension is a pre-existing hypertensive condition or hypertension diagnosed within the first 20 weeks of pregnancy. Racial differences in mortality Another disturbing finding was significant racial differences in mortality trends with Black women having a three- to four-fold increased risk of dying from hypertension-related causes compared to white women. “The rate of mortality began to increase in Black women as young as 15 years old. That increase was seen at 25 years or greater in whites. It suggests not only are Black women at increased risk of dying in general, they have an increased risk of dying from chronic hypertension 10 years earlier than white women,” Dr. Ananth told The Medical Post. Genetics likely plays a big role along with socio-demographic issues. Other trends were seen such as increases in rates of obesity, BMI, diabetes and other conditions associated with hypertension risk. There was also a trend for more women to undergo pregnancy at older ages. Overall, the strongest associations with hypertension-related maternal deaths were in women age 45 to 49 and obesity. “People don’t think chronic hypertension is a big deal, but it is a huge deal,” he said. “Sadly many women don’t know they have hypertension before pregnancy.” In Canada, the Hypertension Canada’s 2020 Comprehensive Guidelines for the Prevention, Diagnosis, Risk Assessment, and Treatment of Hypertension in Adults and Children include some guidance on the management of hypertension in women planning pregnancy. “They recommend that the possibility of pregnancy should be considered, and tested for, in all women of reproductive age with a new diagnosis of hypertension. They estimate that approximately 5% of women will have chronic hypertension when they become pregnant,” said Dr. Mulvagh. The Society of Obstetrics and Gynecology of Canada (SOGC) also offers guidelines, but aren’t easily accessible by non-SOGC members, said Dr. Kara Nerenberg, associate professor of obstetrics and gynecology at the University of Calgary. “However, both Hypertension Canada and SOGC’s guidelines only address the increased maternal mortality rate in women with chronic hypertension at a high level,” she said Dr. Nerenberg led the Hypertension Canada guideline for pregnancy and told the Medical Post that a new guideline, available later this year, will further address hypertensive disorders of pregnancy. Doctors should also keep in mind hypertension which develops after 20 weeks of gestation, preeclampsia, occurs in an additional 5% to 10% of pregnancies, and is also associated with elevated cardiovascular risk. Dr. Mulvagh noted that a new multidisciplinary field recently developed, “cardio-obstetrics,” which recognizes that women with hypertensive pregnancy disorders have a significantly greater risk for earlier and more frequent development of CVD. Canada also has several tertiary care centres with programs specializing in postpartum CVD prevention, such as the Maternal Health Clinic in Kingston, Ont., led by Dr. Graeme Smith. “Dr. Smith’s clinic was one of the first internationally in this field. It provides a one-time consult to women who have experienced a range of pregnancy complications. As a result of his work, there are now about 18 clinics across Canada,” said Dr. Nerenberg. Dr. Nerenberg offered some tips for doctors: Preconception consultation to ensure women are aware of their own risks and fetal risks during pregnancy. Use “pregnancy-friendly” medications. Ensure that women with chronic hypertension receive low dose aspirin between 81-162 mg at bed time before 14 weeks of pregnancy to lower the risk of preeclampsia on top of chronic hypertension. Encourage physical activity of 150 minutes per week and follow Obesity Canada’s recommendations for pregnancy weight gain (women who gain above their targets have higher risks of preeclampsia). During pregnancy, blood pressure management should involve an interdisciplinary team— family physicians, internists, kidney specialists, obstetricians, maternal-fetal medicine specialists depending on local availability. Dr. Mulvagh also encourages people to wear red on Feb. 13 this year as part of the Wear Red Canada women’s heart disease awareness event sponsored by the Canadian Women’s Heart Health Alliance.

Study finds 15-fold increase in maternal deaths related to chronic hypertension

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