Chronic Hypertension During Pregnancy Has Doubled in Recent Years: Study

Despite significant increases in the number of pregnant women experiencing hypertension in recent years, a new study reveals that only about six in ten are treated for the condition with medication, largely due to concerns about the risk of pregnancy side effects linked to prescription drugs.

Hypertensive disorders are a leading cause of pregnancy-related fatalities in the U.S., accounting for roughly 30% of all deaths during delivery. They contribute to the maternal death rate in the U.S. being the highest of any wealthy nation in the world, and the rates of chronic hypertension during pregnancy are continuing to rise.

In findings published this week in the medical journal Hypertension, researchers from Stanford University warn that nearly 4% of pregnant women suffered chronic hypertension during pregnancy in 2021, indicating that the numbers have continued to rise even after new hypertension guidelines were released by the American College of Cardiology (ACOG) and the American Heart Association in 2017.

Pregnancy Hypertension Health Risks

In 2021, researchers highlighted the rising maternal death rates in the United States, especially among minorities, with Black mothers facing the highest death rates during and after delivery.

Hypertensive disorders during pregnancy can include chronic hypertension, as well as preeclampsia and eclampsia, which also account for a large number of maternal deaths in the U.S.

Preeclampsia is a serious condition that can affect every organ in the body and can progress rapidly from seizures to stroke and even lead to death. A number of other studies have previously highlighted how many hospitals are not doing enough to prevent preeclampsia deaths, which could be greatly reduced.

Chronic hypertension is characterized by high blood pressure that either existed before pregnancy or is diagnosed before the 20th week of pregnancy. Unlike gestational hypertension, which develops during pregnancy and typically resolves after childbirth, chronic hypertension persists both before and during pregnancy and may continue after the baby is born. The condition requires careful management to prevent complications for both the mother and the baby.

In this latest study, a team of Stanford researchers, led by Stephanie Leonard of the Department of Obstetrics and Gynecology, looked at data on chronic hypertension during pregnancy from a commercial insurance claims database from 2007 to 2021. The researchers analyzed rates of chronic hypertension during pregnancy and how it was treated.

According to the data, which looked at nearly 2 million pregnancies, the prevalence of chronic hypertension increased from 1.8% of pregnant women in 2007, to 3.7% by 2021. Medication use was stable, but only 57%–60% of pregnant women who needed them received antihypertensive medications, with a shift from methyldopa and hydrochlorothiazide to labetalol and nifedipine over the course of the study.

Leonard and her team determined that the 2017 hypertension guidelines did not significantly affect the prevalence or treatment. They theorized that the flat use of medications to treat pregnancy hypertension might be attributed to ACOG’s cautious approach in endorsing these medications.

“The prevalence of chronic hypertension during pregnancy doubled between 2008 and 2021 in a nationwide cohort of individuals with commercial insurance. Labetalol replaced methyldopa as the most commonly used antihypertensive during pregnancy,” the researchers concluded. “However, only about 60% of individuals with chronic hypertension in pregnancy were treated with antihypertensive medications.”