Treating Pregnancy Hypertension Reduces Maternal Risk

Tackling hypertensive disorders of pregnancy (HDP) can reduce severe hypertension risk without increasing fetal and neonatal risks, according to a new scientific statement issued by the American Heart Association (AHA).

The statement, drafted by researchers at Mayo Clinic (Rochester, MN, USA), Weil Cornell Medical College (New York, NY, USA), and other institutions, includes a review of the current literature on normal physiological changes in pregnancy that may affect clinical presentation of HDP; epidemiology and immediate and long-term sequelae of HDP; the pathophysiology of preeclampsia; an overview of current national and international HDP guidelines; and the increasingly recognized morbidity associated with postpartum hypertension/preeclampsia.

According to the statement, among high-income countries, the United States has one of the highest hypertensive-related maternal mortality rates, accounting for up to half of all maternal deaths, with pregnancy-related stroke hospitalizations increased more than 60% from 1994 to 2011. In addition, preeclampsia affects 5-7% of pregnancies and is responsible for more than 70,000 maternal deaths and 500,000 fetal deaths worldwide every year.

The new AHA statement finds that blood pressure-lowering therapy for HDP significantly reduces the incidence of severe hypertension, supports maternal health both during and after pregnancy, and does not appear to negatively impact fetal growth or development. They also affirm that reducing severe hypertension may be particularly important in communities that lack resources and expertise to respond to hypertension emergencies.

The statement also reinforces recent research that suggests lifestyle changes implemented before and during pregnancy have the potential to improve maternal and fetal outcomes, including dietary changes to limit weight gain and improve pregnancy outcomes and exercise, which may reduce gestational hypertension risk by about 30% and preeclampsia risk by about 40%. The AHA statement was published on December 15, 2021, in Hypertension.

“It is reassuring to see emerging evidence that treating high blood pressure during pregnancy is safe and effective and may be beneficial at lower thresholds than previously thought,” said chair of the statement writing group Professor Vesna Garovic, MD, PhD, of the Mayo Clinic. “Future studies should address whether lowering the threshold for treating hypertension during pregnancy might allow for safe and timely blood pressure control and avoid a rushed delivery because of uncontrolled hypertension.”

HDP, defined as systolic pressure of 140 mm Hg or higher, is the second leading cause of maternal death worldwide. Severe cases are associated with increased risks of cardiovascular complications for mothers immediately or soon after delivery, and for years after pregnancy. HDP also increases risk for complications for the offspring such as preterm delivery, small for gestational age, and low birthweight.

Related Links:
Mayo Clinic
Weil Cornell Medical College