Here’s Why High Blood Pressure Rates Are on the Rise for Pregnant Women in the U.S.

During pregnancy, chronic high blood pressure (hypertension) can cause severe complications for you and your baby.

Now new research finds that chronic hypertension rates in older pregnant women have skyrocketed since 1970 — with potentially severe consequences.

“What’s really happening with this condition? Is it increasing or decreasing, or is it remaining the same? This has never been addressed in the literature, so in some sense, this is perhaps the first, largest population-based study in the United States that looked at this topic,” Cande V. Ananth, PhD, MPH, lead study author and chief of the division of epidemiology and biostatistics in the department of obstetrics, gynecology, and reproductive sciences at Rutgers University, told Healthline.

“Our findings reveal that a very simple condition of increased blood pressure in pregnancy can have very profound, devastating complications to both the mother and the fetus,” he added.

Increase due to advanced age at pregnancy

Using data from the National Hospital Discharge SurveyTrusted Source, researchers from Rutgers Robert Wood Johnson Medical School analyzed the pregnancies of more than 151 million women in the United States from 1970 to 2010.

“We know a lot about chronic hypertension in the literature, and when I read the literature, it really shocked me that there aren’t good studies characterizing the trends in rates of chronic hypertension in pregnant women,” Ananth said.

Study findings suggest the increase was solely due to the trend for increasing age at pregnancy, rather than smoking or obesity.

Researchers found the rate of chronic hypertension has increased by an average of 6 percent per year to 13 times what it was in 1970.

African American women most affected

“Some of the findings were really stunning, particularly the rates of chronic hypertension increasing more than thirteenfold over 40 years, which was really surprising. I did share the results with three of my colleagues, and they were also pretty shocked when they saw that,” admitted Ananth.

“The next most interesting finding was an unexpected, but very persistent, black/white disparity in the prevalence rates. Black women have consistently had two- or threefold increase for many obstetrical complications, and we can now add chronic hypertension to that literature. While this wasn’t a stunning finding, it did surprise us,” Ananth said.

Dr. Kecia Gaither, MPH, FACOG, double board-certified in OB-GYN and maternal fetal medicine, director of perinatal services at NYC Health + Hospitals/Lincoln, says women over 35 also have a higher risk if they have chronic hypertension or diabetes.

“[They] need to have their blood pressure controlled prior to becoming pregnant, decrease weight if obese, exercise, and opt for healthier diets, consisting more of fruits, vegetables, and refrain from high fat and salty foods,” Gaither said.

She adds medical exams such as an EKG, echocardiogram, and ophthalmologic and renal evaluations can be done early in the pregnancy to assess whether there’s any damage already, and steps can be taken to help safeguard the pregnancy.

“Initiation of baby aspirin and supplementation with vitamin D and calcium are also recommended,” Gaither said.

A profound effect on mother and child

Ananth says chronic hypertension is one of the most poorly studied obstetrical complications.

“The condition is as simple as an increase in the blood pressure. That’s it. If the blood pressure exceeds a certain threshold, then women are diagnosed with having chronic hypertension,” Ananth said.

“But it’s not received the kind of attention it truly deserves,” he added, “even though this condition can have profound effects on both the mother in her pregnancy and the fetus.”

Women who have high blood pressure during pregnancy also have a higher risk for stroke and other cardiovascular events after giving birth, according to the Centers for Disease Control and Prevention (CDC)Trusted Source.

Ananth points out that if women aren’t monitored for chronic hypertension, it can put the pregnancy at risk.

“Whether or not the fetus survives could depend on whether the mother has chronic hypertension, so the rates of fetal loss or fetal demise is very high, particularly in women that go unchecked for chronic hypertension. She has a strong potential of losing the pregnancy, delivering early, and the complications that come with that,” he cautioned.