Hypertension problem in pregnancy (HDP) remain one of the major causes of pregnancy-related maternal and fetal morbidity and mortality worldwide. Affected women are also at increased risk for cardiovascular disease later in life, independently of traditional cardiovascular disease risks. Despite the immediate and long-term cardiovascular disease risks, recommendations for diagnosis and treatment of HDP in the United States have changed little, if at all, over past decades, unlike hypertension guidelines for the general population. The reasons for this approach include the question of benefit from normalization of blood pressure treatment for pregnant women, coupled with theoretical concerns for fetal well-being from a reduction in utero-placental perfusion and in utero exposure to antihypertensive medication. This report is based on a review of current literature and includes normal physiological changes in pregnancy that may affect clinical presentation of HDP; HDP epidemiology and the immediate and long-term sequelae of HDP; the pathophysiology of preeclampsia, an HDP commonly associated with proteinuria and increasingly recognized as a heterogeneous disease with different clinical phenotypes and likely distinct pathological mechanisms; a critical overview of current national and international HDP guidelines; emerging evidence that reducing blood pressure treatment goals in pregnancy may reduce maternal severe hypertension without increasing the risk of pregnancy loss, high-level neonatal care, or overall maternal complications; and the increasingly recognized morbidity associated with postpartum hypertension/preeclampsia. Finally, we discuss the future of research in the field and the pressing need to study socioeconomic and biological factors that may contribute to racial and ethnic maternal health care disparities.
Hypertensive disorders of pregnancy (HDP) encompass chronic hypertension, gestational hypertension, preeclampsia/eclampsia, and preeclampsia superimposed on chronic hypertension. The diagnostic criteria for HDP in the United States have evolved over the past 5 decades1; the most current definition of hypertension in pregnancy from the American College of Obstetricians and Gynaecologists (ACOG) was published in 2013, with updates and recommendations made in 2019 and 2020 (Table S1 and Table S2 in the Supplemental Material). Most guidelines around the world are aligned in defining hypertension in pregnancy as blood pressure (BP) ≥140/90 mm Hg (see the Treatment of Hypertension in Pregnancy section). There is variability in the threshold for initiating antihypertensive treatment attributable to uncertainty about the maternal benefits of lowering BP and the potential fetal risks from medication-induced reductions in utero-placental circulation and in utero exposure to antihypertensive medications. In contrast, diagnostic and treatment thresholds for the general population have evolved over the years; in the 2017 American College of Cardiology/American Heart Association (AHA) Hypertension Clinical Practice Guidelines, the threshold for the diagnosis of stage 1 hypertension was further lowered to 130/80 from 140/90 mm Hg on the basis of observational studies and clinical trials demonstrating reduced cardiovascular disease (CVD) events with treatment to lower levels.
This scientific statement presents a synthesis of the scientific evidence (from literature published until August 31, 2020) that is relevant to the current controversies concerning HDP diagnostic and treatment strategies. It is a timely statement given that current trends indicate that the incidence of HDP continues to increase as a result of advanced age at first pregnancy and increased prevalence of obesity and other cardio metabolic risk factors. CVD, including cerebrovascular accidents and cardiomyopathy, now accounts for up to half of all maternal deaths. Pregnancy-related stroke hospitalizations increased >60% from 1994 to 2011, and HDP-associated stroke rates increased 2-fold compared with non–HDP-related stroke. Thus, in the discussion that follows, we emphasize the need for future research aimed at recognizing and appropriately treating HDP.
HDP are the second leading cause of global maternal mortality behind maternal hemorrhage12 and are a significant cause of short- and long-term maternal and fetal/offspring morbidity (Tables 1 and 2). Elevated systolic BPs throughout pregnancy, even below the diagnostic threshold for hypertension, also are associated with increased risk of preterm delivery and infants who are small for gestational age and have low birth weight.