Jul 11, 2024 By Kristin Emery 4 min read

The number of individuals in the U.S. who had chronic hypertension or chronic high blood pressure during pregnancy doubled between 2008 and 2021, according to a new study published in Hypertension, a journal of the American Heart Association. At the same time, prescribing and filling of antihypertensive medication during pregnancy remained low but stable at 60%. Some of the data comes from a nationwide review of private health insurance claims.

Chronic hypertension in pregnancy is defined as high blood pressure diagnosed before pregnancy or before 20 weeks of pregnancy. Recent research has suggested that medication treatment of mild or moderate high blood pressure during pregnancy reduces the risk of severe hypertension and preeclampsia, a condition which can cause liver or kidney damage and may double chances for future cardiovascular complications including heart failure. Thresholds for high blood pressure stand at 130/80 to 140/90 mm Hg for stage one. Some doctors lament the fact that those guidelines, which were revised in 2017, have not led to better or more treatment of the condition.

The study shows the rate of high blood pressure diagnosis steadily increased from 1.8% to 3.7% among 1.9 million pregnancies between 2008 and 2021. A higher proportion of patients with high blood pressure were over age 35 and had other chronic health conditions such as obesity, diabetes or kidney disease. During that period, use of medication for high blood pressure treatment during pregnancy remained low and relatively stable.

Are doctors seeing this same trend in higher blood pressure during pregnancy in our region? “Yes, the past several years in our practice we have seen an increase in gestational hypertension,” says Dr. Nicole Garcher of UPMC Washington OB/GYN Care. “Gestational hypertension is defined as a systolic blood pressure of 140mm Hg or more, or a diastolic blood pressure of 90mm Hg or more, on two separate occasions at least four hours apart – after 20 weeks of gestation. Up to half of women with gestational hypertension will eventually develop preeclampsia.”

She points to several factors as possible reasons for the increase. Obesity (women with BMI >30), age (older than 35), history of chronic hypertension, history of diabetes and history of kidney disease can all play a role.

Gestational hypertension is worrisome because it can lead to preeclampsia.

“This can affect all organs of the body,” says Garcher. “It is associated with elevated blood pressure as well as kidney injury, which can be seen by elevated protein in the urine. It can cause headaches, chest pain, abdominal pain, and liver abnormalities.” Even worse, it can lead to an emergency medical condition that causes seizure and stroke associated with HELLP syndrome (which stands for Hemolysis, Elevated Liver enzymes, Low platelet count). Pregnant women aren’t the only ones at risk from gestational diabetes. The fetus is also at risk of low birth weight, low amniotic fluid levels, and preterm delivery.

Warning signs

Women should watch for elevated blood pressure, headaches that do not improve with Tylenol and pain in the upper right side. Doctors monitor pregnant mothers at their OB visits through blood pressure checks and routine urine screening for protein. They may also do lab tests to check kidney and liver function.

Garcher says the goal for managing the condition is to limit complications for mom as well as to deliver a healthy baby.

“Women with preeclampsia without severe features may be treated in hospital or as an outpatient,” she said. “We encourage daily kick counts as well as at home blood pressure monitoring. We may also recommend additional testing in the form of twice per week visits including a non-stress test (to test fetal wellbeing) and additional ultrasounds. If testing shows the fetus is not doing well, we would plan for earlier delivery prior to 37 weeks.”

In her practice, she generally tries to avoid prescribing medication for the condition but says she sometimes will recommend antihypertensive medication for patients with chronic high blood pressure.

“For the majority of patients, blood pressure does seem to normalize between six and eight weeks postpartum,” she added. “Though women with a history of gestational hypertension are at increased risk for developing chronic hypertension in the future. This can be due to genetics, obesity and aging.”