Chronic hypertension in pregnancy

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.

Also called Chronic hypertension

Condition
In this atlas

Overview

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.

Burden

No burden claims are published.

Claims and evidence

No claims are published for this condition yet.

Clinical links

Each link reports what one cited claim says about one population. "Evaluated for" means studied, not shown to work. These links do not show that anything is effective or right for you.

Claim, not a settled fact Evaluated for this: Antihypertensive drug treatment for non-severe hypertension in pregnancy (Evaluated for, seen from the other side)
Applies to Mixed recipients
- The same women as the maternal CHAP context, with the outcomes of their pregnancies. The primary composite combines a maternal event (pre-eclampsia with severe features up to 2 weeks after birth), pregnancy events (medically indicated preterm birth before 35 weeks and placental abruption) and a fetal or neonatal event (fetal or neonatal death). It is used only for the composite as the trial defined it and is never split by recipient.
- Recruiting sites of the CHAP Trial Consortium in the United States; see the maternal CHAP context.
- United States
- Pregnancy and the newborn period
- Gestational age Not reported
- Postnatal age Not reported
Follow-up Pre-eclampsia counted up to 2 weeks after birth. Fetal or neonatal death is listed at under 28 days in the manuscript table; the registry gives up to 90 days for neonatal death.
In the CHAP trial in the United States, women with mild chronic hypertension who enrolled before 23 weeks of pregnancy and were treated to a blood-pressure goal below 140/90 mm Hg had fewer of the combined serious pregnancy problems than women whose treatment was held back unless their blood pressure became severe. The combined outcome (pre-eclampsia with severe features, a medically indicated preterm birth before 35 weeks, placental abruption, or the death of the fetus or newborn) occurred in 353 of 1170 women with outcome data in the treated group (30.2%) and 427 of 1155 in the control group (37.0%). A separate analysis that fills in missing outcomes gave an adjusted risk ratio of 0.82 (95% CI 0.74 to 0.92).
Limitations. Open-label trial in one country, so women and clinicians knew the assigned strategy. The composite mixes a maternal event with pregnancy events and fetal or neonatal events; the sources do not split it by recipient and the atlas does not either. The percentages and counts come from the complete-case analysis (2325 of 2408 women had enough data); the adjusted risk ratio comes from a multiple-imputation analysis of all 2408. They are different analyses. The authors’ secondary composites of serious maternal complications and of severe neonatal complications did not show clear differences in the abstract; they are about the mother and the newborn separately, so they are not recorded here as claims of their own. Secondary results were not adjusted for multiplicity. For women with newly diagnosed hypertension and for a body-mass index of 40 or more, the risk ratios were close to 1.00 with wide intervals. About 12 women were screened for each woman randomized. The sample size was reduced from a planned 4700 women to a final 2404 that the data and safety monitoring board approved, and the abstract and the Methods word the upper blood-pressure limit differently (below 160/100 vs below 160 and below 105 mm Hg). The registry calls the primary outcome perinatal although it includes a maternal event.

Record details

Record id: maternal:chronic-hypertension-in-pregnancy
Content hash: d6df99cc44c48ed4728683b223ce117a35b759535e952de94c8f6e9dfd35f292