Detection of hypertension and blood pressure phenotypes using ambulatory blood pressure monitoring in women with past hypertensive disorders of pregnancies

OBJECTIVE: To evaluate the incidence of hypertension and blood pressure (BP) phenotypes using 24-hour ambulatory BP (24hr-ABP) in women with past pregnancy complications who were recruited into a Women's Heart Clinic (WHC). STUDY DESIGN: We recruited 156 women aged 30-55 years with past hypertensive disorders of pregnancy (HDP) and/or gestational diabetes (GDM) to a multidisciplinary six-month WHC that provided cardiovascular risk management in Melbourne, Australia. Women were referred for 24 hr-ABP monitoring if clinic BP was ≥130/80 mmHg. MAIN OUTCOME MEASURES: Primary outcome was incident hypertension, defined by 24 hr-ABP monitoring as daytime hypertension ≥135/85 mmHg, nocturnal hypertension ≥120/70 mmHg, and/or 24hr-average hypertension ≥130/80 mmHg. RESULTS: From 156 women, 54 women underwent 24hr-ABP monitoring (mean age 41.3 ± 4.5 years; 3.9 ± 2.6 years post-partum), with 64.8 % HDP and 45.2 % GDM. Incidence of hypertension was 61.1 % [95 % CI 48.2 %-74.0 %]. Higher proportion of women with past HDP had daytime hypertension compared to those with GDM only (57.1 % vs. 26.3 %; p = 0.05) and higher nocturnal mean systolic-BP [116.0 ± 11.2 mmHg vs. 109.6 ± 8.7 mmHg; p = 0.04]. Women with HDP had increased odds of hypertension [adjusted-OR 5.26 95 % CI (1.07-32.76); p = 0.05]. Following management at the WHC, women diagnosed with hypertension had significantly improved BP control (6.1 % at baseline vs. 75.8 % at six-month follow-up; p < 0.001). CONCLUSION: Women with past HDP had five-fold increased incidence of hypertension, with higher daytime hypertension and nocturnal systolic-BP, compared to women with GDM. After attending WHC, BP control significantly improved. Our findings suggest routine postpartum follow-up with 24hr-ABP monitoring, through a WHC, may be useful in early detection and management of hypertension in these women.