Effects of Antihypertensive Therapy During Pregnancy on Postpartum Blood Pressure Control.

Objective: To compare differences in postpartum blood pressure (BP) control (BP below 140/90 mm Hg) for participants with hypertension randomized to receive antihypertensive treatment compared with no treatment during pregnancy.

Methods: This study was a planned secondary analysis of a multicenter, open-label, randomized controlled trial (The CHAP [Chronic Hypertension and Pregnancy] trial). Pregnant participants with mild chronic hypertension (BP below 160/105 mm Hg) were randomized into two groups: active (antihypertensive treatment) or control (no treatment unless severe hypertension, BP 160/105 mm Hg or higher). Study outcomes were BP control below 140/90 mm Hg (primary) and medication nonadherence based on a composite score threshold (secondary) at the 6-week postpartum follow-up visit. Participants without follow-up BP measurements were excluded from analysis of the BP control outcome. Participants without health care professional-prescribed antihypertensives at delivery were excluded from the analysis of the adherence outcome. Multivariable logistic regression was used to adjust for potential confounders.

Results: Of 2,408 participants, 1,684 (864 active, 820 control) were included in the analysis. A greater percentage of participants in the active group achieved BP control (56.7% vs 51.5%; adjusted odds ratio [aOR] 1.22, 95% CI, 1.00-1.48) than in the control group. Postpartum antihypertensive prescription was higher in the active group (81.7% vs 58.4%, P<.001), and nonadherence did not differ significantly between groups (aOR 0.81, 95% CI, 0.64-1.03).

Conclusion: Antihypertensive treatment of mild chronic hypertension during pregnancy was associated with better BP control below 140/90 mm Hg in the immediate postpartum period.