Addressing high blood pressure during and after pregnancy can significantly reduce maternal mortality rates and improve women's heart health even after child-bearing years, according to insights gained from a longitudinal study of pregnant women.
Heather M. Johnson, MD, preventive cardiologist with Baptist Health Christine E. Lynn Women's Health & Wellness Institute at Boca Raton Regional Hospital was one of the lead researchers on the study, published in The Journal of Maternal-Fetal Medicine in December 2021.
Between 2017 and 2020, researchers analyzed data to determine longitudinal blood pressure patterns from preconception to 42 days postpartum in women diagnosed with hypertensive disorders of pregnancy (HDP).
In one significant finding, researchers learned that about a quarter of the women continued to have high blood pressure after their six-week OB checkup
"Hypertensive disorders of pregnancy can continue much longer than we thought," Dr. Johnson notes. "If we can address this and control high blood pressure, we can keep many women from being readmitted to the hospital after delivery with life-threatening emergencies, such as heart failure, stroke and other cardiovascular events. Blood pressure plays a critical role in these conditions."
Maternal Mortality in the U.S.
The maternal mortality rate in the U.S. sits at 17.4 per 100,000 live births, according to the most recent figures from the Centers for Disease Control and Prevention. Hypertension may be responsible for more than a third of maternal deaths, according to the study.
In addition, wide racial and ethnic gaps also exist in the U.S., according to the CDC:
- 37.3 deaths per 100,000 live births for non-Hispanic black mothers
- 14.9 for non-Hispanic white women
- 11.8 for Hispanic women
The U.S. rate is several times higher than similar high-resource nations. For example, according to the World Health Organization, the maternal mortality ratio is:
- 4 per 100,000 women in Sweden
- 5 per 100,000 in Japan
- 6 per 100,000 in Australia
Study details and findings
Researchers analyzed blood pressure patterns of 964 women diagnosed with HDP during pregnancy or postpartum in the study between 2017 and 2020 in Madison, Wisconsin.
After delivery, the women were discharged with home blood pressure cuffs and transmitted data daily through a secure telehealth system. In addition, they received daily follow-up phone calls from a nurse.
Study highlights include:
- High blood pressure was defined as a reading of 140/90 or above on two occasions at least four hours apart
- Data was collected from 47 time points from preconception to day 42 postpartum
- The highest average systolic blood pressure, 131.9 mmHg, was reached on delivery day.
- The highest percentage of hypertension spikes for all the women – between 140/90 and 150/100 – occurred on postpartum day five.
- For nearly 26% of women, hypertension was not resolved by postpartum day 42.
Home blood pressure monitoring and postpartum warning signs
Dr. Johnson and her colleagues were alarmed by how often hypertension continues after delivery. In most cases, this happens after women are discharged but before their first scheduled OB follow-up at six weeks.
Some women in the study were prescribed medication for hypertension in that timeframe to prevent serious complications.
"The traditional time frame that some women may follow up after delivery may be too long because we are seeing such a change in blood pressure within the first week after delivery," Dr. Johnson said. "When women are receiving advice in the hospital about breastfeeding and their recovery, we are encouraging healthcare providers across the country to also discuss high blood pressure and the importance of home blood pressure monitoring."
Before women are discharged, they should know about warning signs that can signal a cardiac emergency, such as:
- Fast heart rate
- Chest discomfort
- Shortness of breath
- Swelling in the lower legs, ankles or stomach
Women also should know who to call during the day or after hours if they notice these symptoms.
Addressing unresolved postpartum high blood pressure
For the nearly 26% of women whose hypertension was still a problem after their six-week checkup, Dr. Johnson recommends a partnership between obstetrics and cardiology care.
Dr. Andrea Vitello, cardiologist with Baptist Health Miami Cardiac & Vascular Institute agrees. She says, "We need to better understand how pregnancy affects the cardiovascular system at various stages. This study underscores the need for a collaborative approach to this high-risk population."
If women diagnosed with HDP are referred to a cardiologist during their pregnancy, cardiologists can look for specific causes of hypertension, such as structural issues, with an EKG, heart ultrasound or other cardiac tests.
Dr. Johnson also recommends a preconception visit with an obstetrician or cardiologist for women who have high blood pressure before pregnancy. During the appointment, the doctor can adjust the current hypertension medication if it is not safe for pregnancy.
Primary care providers and long-term implications
"As women transition after delivery to ongoing medical care, it's very important for their primary care provider to be aware of their risk for ongoing high blood pressure or developing high blood pressure down the road," Dr. Johnson notes.
If women have HDP, including preeclampsia or eclampsia, they have a 15% risk or higher of developing high blood pressure during subsequent pregnancies. Pregnancy-related hypertension is also a risk factor for hypertension long after women have had their children.
When providers consider cardiac risk factors for women, HDP should be added to the list, she advises. She also recommends further study of racial and ethnic differences in maternal mortality, what conditions affect HDP and long-term implications of HDP in women's overall risk of a heart attack.
"Our goal is to keep women out of the hospital," Dr. Johnson said. "We want to help them lower their risk of heart disease and heart events by addressing blood pressure as an important factor."
Baptist Health Christine E. Lynn Women’s Health & Wellness Institute at Boca Raton Regional Hospital provides women in South Florida with a continuum of care that addresses a woman’s unique medical needs, from young adult through menopause and beyond. The Institute's commitment to providing the most advanced clinical and diagnostic services includes participation in research studies that uncover better ways of improving health and lessening the burden of disease. To refer a patient to Baptist Health Christine E. Lynn Women’s Health & Wellness Institute, call 561-955-2131.
Baptist Health Miami Cardiac & Vascular Institute, a renowned center of excellence in cardiovascular care, is the region’s largest and most comprehensive cardiovascular facility. The Institute leverages the power of Baptist Health’s combined resources of experts, pioneering research, compassionate caregivers, and leading-edge treatments and technology. To refer a patient to Baptist Health Miami Cardiac & Vascular Institute, call 786-204-4200.