A comparative analysis of blood pressure categorization using 24-hour ambulatory blood pressure monitoring in young women with presumed chronic hypertension with and without a history of pregnancy

BACKGROUND: Hypertension among childbearing-age women is often underrecognized, undertreated, and when diagnosed, misclassified. Accurate diagnosis of hypertension is imperative, especially in cases of pregnancy because it directly influences medical management, delivery plan, and treatment decisions. OBJECTIVE: This study aimed to assess the 24-hour ambulatory blood pressure monitoring results of women from the MyHEART trial who had a presumed clinical diagnosis of chronic hypertension, and to determine the incidence of masked, white coat, nocturnal, and confirmed hypertension. Secondarily, we also assessed self-reported pregnancy history and the impact of having a prior pregnancy with or without hypertension on their 24-hour ambulatory blood pressure monitoring results. STUDY DESIGN: We conducted a secondary analysis of the data from 221 women who completed 24-hour ambulatory blood pressure monitoring during a preenrollment visit to confirm eligibility for the MyHEART trial. All women, regardless of whether they enrolled in the trial, were interviewed via phone about their history of pregnancy, hypertensive disorders of pregnancy, and/or antihypertensive medication use. Statistical analysis was performed using R software and Mann-Whitney-Wilcoxon and chi-square tests. RESULTS: Among 221 women, 142 (64.3%) had confirmed chronic hypertension, 73 (33.0%) had white coat hypertension, 56 (25.3%) had nocturnal hypertension, and 43 (19.5%) had masked hypertension according to 24-hour ambulatory blood pressure monitoring results. The incidence of confirmed chronic, white coat, masked, or nocturnal hypertension in the 55 women with a history of pregnancy did not differ significantly compared with women without a history of pregnancy. Additionally, 47 of the 55 women reported hypertension during pregnancy, but their ambulatory blood pressure monitoring results were not affected by the specific hypertensive diagnosis assigned during pregnancy. Within this subgroup, the ambulatory blood pressure monitoring results varied by race. On average, Black women had significantly higher ambulatory systolic blood pressure readings and an increased incidence of nocturnal hypertension compared with their White counterparts. CONCLUSION: The integration of diagnostic tools such as 24-hour ambulatory blood pressure monitoring or, alternatively, home blood pressure monitoring for women with elevated blood pressures-particularly those of childbearing age-allows for more precise classification of hypertension. Accurate diagnosis supports optimal medical management and treatment decision-making, including during pregnancy, and helps avoid unnecessary interventions in individuals with white coat hypertension. Ultimately, improved diagnostic clarity enhances our ability to deliver tailored, evidence-based care by providing a more nuanced understanding of each patient's blood-pressure profile.