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Health officials are concerned about pregnant women developing high blood pressure. Getty Images
  • High blood pressure, or hypertension, is on the rise in pregnant women in the United States.
  • One key reason is that women are having children later in life.
  • But other factors include women who have diabetes or other medical conditions when they become pregnant.

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.

Using data from the National Hospital Discharge Survey, 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.

“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.

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).

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.

The health risks of chronic hypertension during pregnancy aren’t limited to the 40-week period until the baby is born. Recent research has found it can have a significant effect on the mother’s long-term health.

And infants born to women who had gestational hypertension have an increased chance for certain health conditions later in life.

“Very recent studies — and this is just the literature — it’s just beginning to emerge that women who have chronic hypertension have lasting effects on cardiovascular disease later in life, 20, 30, 40 years later,” Ananth said.

“There is a very high risk of cardiovascular complications compared to women who don’t have chronic hypertension. So, not only are the effects of chronic hypertension immediate in the pregnancy and the newborn, but even far out, long-term implications,” he said.

Dr. Jie Hu, PhD, a postdoctoral researcher in the division of women’s health in the department of medicine at Brigham and Women’s Hospital, said in a statement that accurate diagnosis of gestational hypertension is crucial to preventing serious complications that can have long-lasting implications on the infant.

“Infants born to women with gestational hypertension are more susceptible to preterm birth and adverse long-term health outcomes, like young adulthood cardiovascular diseases,” she said.

The average age of first-time mothers has increased in the United States over just the past 10 years, according to a data brief released by the CDC.

The CDC also reports that the rate of teen pregnancy has also reached historic lows. This means the trend of increasing age at pregnancy isn’t likely to change in the foreseeable future.

Ananth says one solution to the growing rates of hypertension is making healthy lifestyle changes.

“Women need to better control their blood pressure before and during pregnancy. Smoking cessation, weight control, behavioral changes, and effective anti-hypertensive therapy — all modifiable factors — may lead to healthier lifestyle and will likely have a substantial beneficial effect on chronic hypertension and pregnancy outcomes,” Ananth said in a statement.

Gaither emphasizes recent medical advances make healthy pregnancy possible for older women.

“With the technologic and medical advances that currently exist, one can say there really is no ‘healthiest age range’ to become pregnant,” she said.

“For any woman who wishes to become pregnant, certainly a visit to her medical provider in the preconceptual period is of paramount importance to optimize any comorbid health condition she may have to ensure she has the healthiest perinatal experience and outcome for both her and her baby,” Gaither said.

The average age women become pregnant in the United States has been steadily increasing over the past 40 years. Recent research finds this is strongly associated with a thirteenfold increase in rates of chronic hypertension in pregnant women.

High blood pressure during pregnancy can have severe consequences for both mother and fetus, including losing the pregnancy, premature birth, and the complications associated with preterm delivery.

Experts say that advances in medical technology make healthy pregnancy possible at older ages — but it’s important to speak with your doctor first for the best outcomes.