High Blood Pressure During Pregnancy Has Doubled

The prevalence of chronic hypertension among pregnant people doubled between 2008 and 2021, according to recent research. 

The study, published in the journal Hypertension, also found that about 40% of people with chronic hypertension didn’t get treated with antihypertensive medicines during pregnancy. 

High blood pressure occurs when the force of blood exerted against artery walls in the heart is higher than normal. A doctor diagnoses “chronic hypertension in pregnancy” if someone has a reading of at least 130/80 mm Hg before pregnancy or 20 weeks of pregnancy.

Chronic high blood pressure can raise the risk of developing gestational hypertension—which is diagnosed after 20 weeks—and complications such as preeclampsia, placental abruption, and stillbirth. Left untreated, it can cause hemorrhage, stroke, and other health problems after a patient gives birth.

“This study highlights the growing burden of chronic hypertension and poor cardiovascular health pre-pregnancy as critical targets to improve maternal health,” said Sadiya Khan, MD, a preventive cardiologist at Northwestern Medicine, in a statement. “Since nearly 1 in 3 individuals with chronic hypertension may face a pregnancy complication, the prevention and control of hypertension should be among the highest priorities for improving maternal health.”

To assess the rate of chronic hypertension during pregnancy, researchers analyzed commercial insurance claims from 2007 to 2021, including nearly 2 million pregnancies from the National Hospital Discharge Survey data. They found that the percentage of pregnant people diagnosed with chronic hypertension shot up from 1.8% in 2008 to 3.7% in 2021.

Only 60% of diagnosed patients received antihypertensive medicines such as labetalol or nifedipine during pregnancy, the research revealed. The rate remained consistent despite a 2017 change in the American Heart Association’s clinical guidelines, which reduced the blood pressure threshold for the treatment of hypertension.

“We were surprised to not find any meaningful changes from before and after the guideline,” Stephanie Leonard, PhD, lead author and an assistant professor of obstetrics and gynecology at the Stanford School of Medicine, said in the statement. “While the rate of hypertension in pregnancy has doubled, the use of medication for treatment remained stable at only 60%, which we believe is likely below what it should be if patients are treated according to clinical guidelines.”

Additionally, the findings highlighted that Black women with other comorbidities who are older than 35 and live in the South had the highest rate of chronic hypertension in pregnancy.

Experts attribute the increase in gestational hypertension to higher rates of obesity, which can raise blood pressure. 

According to the National Institute of Diabetes and Digestive and Kidney Diseases, almost 42% of women in the U.S. have obesity or severe obesity. Overall obesity rates have soared, jumping from 30% in 1999 to 41% between 2017 and 2020.

Indeed, the new research found that 64% of the pregnant people who were prescribed antihypertensive medication during the study timeframe were more likely to have a body mass index (BMI) of 40 or higher, suggesting obesity. (Roughly the same percentage of women also had diabetes or chronic renal disease.) 

Cande Ananth, PhD, a professor in the department of obstetrics, gynecology, and reproductive sciences at Rutgers Robert Wood Johnson Medical School, told Health that another contributing factor is that women are getting pregnant at older ages.

“As women age, they are more likely to have lifestyle diseases,” she said. “They also grapple with declining chances of spontaneous conception.”

According to a study led by Ananth, people who underwent infertility treatments were more than twice as likely to be hospitalized for hypertension than those who conceived naturally.

Another issue has to do with lower rates of diagnosis prior to pregnancy, said Julie Lamppa, APRN, CNM, director of midwifery services at Mayo Clinic.

“I believe that the pure diligence of patient monitoring has gotten more conservative over time,” she told Health. “It is extremely beneficial for patients to have an accurate diagnosis of chronic hypertension before pregnancy. But many are falling through the cracks.”

Experts say that certain lifestyle habits can reduce the chances of having hypertension-related complications during and after pregnancy.

Lamppa recommended lowering sodium intake by choosing home-cooked meals filled with fruits, vegetables, and whole grains. And remember to move your body, she said. Aim for at least 150 minutes of weekly exercise, such as brisk walking or using exercise bands.

“It’s normal and expected to gain weight during a pregnancy,” she explained, “but keeping it within the recommended range will help reduce chances of worsening hypertension.”

Attending routine prenatal visits with your obstetrics provider is also crucial, according to Lamppa. Discuss potential medication with your doctor and tell them about any elevations in blood pressure, which you’ll likely be advised to measure at home.

Finally, try to relax. “Taking a holistic approach to caring for yourself is essential in all pregnancies, but especially when there are conditions that put a pregnancy at higher risk,” Lamppa noted. That said, “the vast majority of pregnant women with hypertension do have good pregnancy outcomes.”