LandmarkRCT

CHAP

Treatment for Mild Chronic Hypertension during Pregnancy

N Engl J Med, 2022 · Multicenter, randomized, pragmatic open-label trial

Clinical question

Does treating mild chronic hypertension in pregnancy to target blood pressure <140/90 mmHg reduce adverse pregnancy outcomes without impairing fetal growth?

Population: 2408 pregnant women with mild chronic hypertension (blood pressure <160/100 mmHg)
Intervention: Antihypertensive therapy (labetalol or nifedipine) targeting BP < 140/90 mmHg (n = 1208)
Comparator: Standard care: no antihypertensive therapy unless severe hypertension (BP >= 160/105 mmHg) developed (n = 1200)
Primary outcome: Composite of preeclampsia with severe features, medically indicated preterm birth <35 weeks, placental abruption, or fetal/neonatal death
Result: Treatment to target <140/90 mmHg significantly lowered the primary composite outcome (30.2% vs 37.0%, RR 0.82, 95% CI 0.74–0.92, P < 0.001) without increasing small-for-gestational-age birth weight (11.2% vs 10.4%, P = 0.56). (RR 0.82 (95% CI 0.74–0.92), <0.001)

What the trial found

Treating mild chronic hypertension during pregnancy to a target below 140/90 mmHg reduces severe adverse maternal and perinatal events without impairing fetal growth.

Current guideline position

Adopted by ACOG and SMFM clinical guidance as the standard blood pressure target in pregnant patients.

Clinical interpretation

Overturned decades of restrictive blood pressure management, defining blood pressure targets of <140/90 mmHg throughout pregnancy.

High certainty

Clinical Context & Relevant Topics (2)

Disease Reference

Obstetric Critical Care

Maternal physiology, preeclampsia/eclampsia, HELLP vs AFLP, postpartum hemorrhage (MTP/TXA), peripartum cardiomyopathy, and arrest.

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Hypertensive Emergencies

Target organ damage assessment, intravenous antihypertensive titration, and emergency-specific blood pressure targets.

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