In reproductive-aged women, the prevalence of hypertension approximates 6 percent (Centers for Disease Control and Prevention, 2017). Thus, not surprisingly, chronic hypertension is one of the most common serious complications encountered during pregnancy. In one study of more than 56 million births, the incidence was 1.8 percent (Bateman, 2012). Chronic hypertension complicated 2.3 percent of pregnancies in data from the Medicaid Analytic Extract (Bateman, 2015). Despite an increasing prevalence from 1970 to 2010, optimal management has not been well studied (Ananth, 2019).
Chronic hypertension usually improves during early pregnancy. This is followed by variable behavior later in pregnancy and may include development of superimposed preeclampsia. The latter carries significant risks for maternal and perinatal morbidity and mortality.
Blood pressure is a polygenic biological variant that differs between populations. Numerous epigenetic factors also influence penetrance differences between individuals. Moreover, clinical features such as increasing age and weight correlate positively with rising pressures. Last, resting blood pressure measurements do not reflect daily activities. Therefore, adults have a broad range of normal blood pressure values, which makes defining hypertension difficult.
Definition and Classification
Chronic hypertension would logically be defined as some level of sustained resting blood pressure that is associated with acute or long-term adverse effects. Most consider 140/90 mm Hg as the upper limit of normal. In the United States, these values were derived primarily from life insurance actuarial tables constructed using data from white adult males. These “norms” disregard ethnicity, gender, and other covariants. The importance of race is emphasized by Kotchen (2018), who cites the incidence of hypertension—defined as blood pressure >140/90 mm Hg—to be 34 percent in blacks, 29 percent in whites, and 21 percent in Mexican Americans.
For many years, the Joint National Committee promulgated guidelines for diagnosis, classification, and management of chronic hypertension. Recently, a coalition led by the American College of Cardiology and the American Heart Association published criteria for the diagnosis of hypertension (Table 53-1) (Whelton, 2018).
TABLE 53-1Criteria for Diagnosis of Hypertension ||Download (.pdf) TABLE 53-1Criteria for Diagnosis of Hypertension
|Blood Pressure (mm Hg) || |
|SBP || ||DBP || || |
| <120 ||and ||<80 ||Normal ||Normal |
|120–129 ||and ||<80 ||Elevated ||Normal |
|130–139 ||or ||80–89 ||Stage 1 HTN ||Normal |
|140–159 ||or ||≥90 ||Stage 2 HTN ||Mild to moderate HTN |
| ≥160 ||or ||≥110 ||Stage 2 HTN ||Severe HTN |
Treatment and Benefits for Nonpregnant Adults
Chronic hypertension accounts for nearly 15 percent of deaths worldwide (Kotchen, 2018). Long term, hypertension raises substantively the risk ...