# Chronic hypertension in pregnancy

Condition · id `maternal:chronic-hypertension-in-pregnancy` · Maternal & Newborn Atlas · release `15708f235d73cd42` (public)

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Also called: Chronic hypertension

Browse, life stage: Preconception; Pregnancy; Postpartum  

## In plain language

High blood pressure that a woman already has when she becomes pregnant, or that is found in the first 20 weeks. It is a form of high blood pressure, but decisions in pregnancy differ: some blood pressure medicines are not advised, and whether to treat mildly raised pressure has been debated.

## Technical summary

Pre-existing or early-pregnancy hypertension. NICE NG133 (terms used): high blood pressure that is found at the first antenatal (booking) appointment or before 20 weeks, or that a woman is already on medicine for when she is referred to maternity care; it can be primary or secondary. NG133 treats a systolic pressure of 140 mmHg or more, or a diastolic pressure of 90 mmHg or more, as hypertension. The CHAP trial used its own entry definition, given on the CHAP trial page, which is close to NICE’s but not identical. NG133 advises stopping ACE inhibitors or ARBs if a woman becomes pregnant. CHAP’s authors describe treatment of mild chronic hypertension in pregnancy as controversial before the trial. Pre-eclampsia can develop in women who have chronic hypertension (NG133 1.3.12). The recipient is the pregnant woman; effects on the fetus or newborn sit in claims with their own contexts.

## Connected pages

- One of the three groups NICE lists under hypertensive disorders of pregnancy: Hypertensive disorders of pregnancy (`maternal:hypertensive-disorders-of-pregnancy`)
- Hypertension that is present before or early in pregnancy: Hypertension (high blood pressure) (`core:hypertension`)
- Related to: Pre-eclampsia (`maternal:preeclampsia`)
- Evaluated for this: Antihypertensive drug treatment for non-severe hypertension in pregnancy (`maternal:antihypertensive-treatment-non-severe-hypertension-pregnancy`) [a claim, not a settled fact; see claim `maternal:claim-chap-primary-composite` and its context]
- Investigated in: CHAP (Chronic Hypertension and Pregnancy) trial (`maternal:chap-trial`)

## Provenance

Content hash: d6df99cc44c48ed4728683b223ce117a35b759535e952de94c8f6e9dfd35f292
Last substantive edit: 2026-10-11
Evidence last checked: Not recorded