Incidence of postpartum hypertension within 2 years of a pregnancy complicated by preeclampsia: a systematic review and meta-analysis.

BACKGROUND: Women with a history of hypertensive disorders of pregnancy (HDP) are at increased long-term risk of cardiovascular disease. However, there has been increasing evidence on the same risks in the months following birth.

OBJECTIVES: This review aims to estimate the incidence of hypertension in the first two years after HDP.

SEARCH STRATEGY: MEDLINE, EMBASE and Cochrane databases were systematically searched in October 2019.

SELECTION CRITERIA: Observational studies comparing hypertension rate following HDP and normotensive pregnancies up to two years.

DATA COLLECTION AND ANALYSIS: A meta-analysis to calculate the odds ratio (OR) with a 95% confidence interval (CI) and a sub-group analysis excluding women with chronic hypertension were performed.

MAIN RESULTS: Hypertension was diagnosed within the first two years following pregnancy in 468/1646 (28.4%) and 584/6395 (9.1%) of the HDP and control groups, respectively (OR=6.28; 95% CI 4.18-9.43; I2 =56%). The risk of hypertension in HDP group was significantly higher in the first six months following delivery (OR=18.33; 95% CI 1.35-249.48; I2 =84%) than at six to twelve months (OR=4.36; 95% CI 2.81-6.76; I2 =56%) or between one to two years postpartum (OR 7.24; 95% CI 4.44-11.80; I2 =9%). A sub-group analysis demonstrated a similar increase in the risk of developing postpartum hypertension after HDP (OR 5.75; 95% CI 3.92-8.44; I2 =49%) and preeclampsia (OR=6.83; 95% CI 4.25-10.96; I2 =53%).

CONCLUSIONS: The augmented risk of hypertension after HDP is highest in the early postpartum period suggesting that diagnosis and targeted interventions to improve maternal cardiovascular health may need to be commenced in the immediate postpartum period.