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OverviewAetiologyPathophysiologyClinical features and red flagsInvestigationsDifferential diagnosisManagementComplicationsMonitoring and follow-upSpecial situationsCommon pitfallsQuestionsSources
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Educational draft · awaiting clinical reviewThe full textbook explains uncertainty but does not replace live national or local guidance, specialist advice, or current prescribing information.

Chronic hypertension and gestational hypertension

Obstetrics and gynaecology · UK scope · Sources checked 7 Sept 2026 · Clinical review pending

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Severe blood pressure requires immediate maternity assessment

A systolic pressure of 160 mmHg or more or diastolic pressure of 110 mmHg or more can precede maternal stroke even when the patient feels well.

Action: Arrange urgent obstetric assessment, repeat the measurement promptly using correct technique, and initiate monitored treatment for persistent severe hypertension while checking neurological symptoms, renal and liver function, platelets and fetal wellbeing.

Overview

Distinguish pre-existing hypertension from new pregnancy-associated hypertension, recognise progression towards pre-eclampsia, and organise effective maternal treatment with appropriate fetal and postnatal surveillance.

The gestational age at which hypertension becomes apparent helps classify disease but cannot replace the history. Obtain pre-pregnancy readings, the booking blood pressure, previous prescriptions and prior pregnancy outcomes. Physiological vasodilatation can lower blood pressure during early pregnancy and temporarily conceal chronic hypertension. Conversely, an isolated raised clinic reading can reflect discomfort or a white-coat effect. Repeat measurements with a validated pregnancy device, suitable cuff and supported arm, documenting both values and symptoms.

Chronic hypertension may be essential or secondary to renal, endocrine or vascular disease. Gestational hypertension develops after 20 weeks without the additional abnormalities that define pre-eclampsia. These categories are provisional clinical descriptions, because someone initially labelled as having gestational hypertension can develop proteinuria, organ injury or fetal growth restriction later. Earlier presentation and more severe blood pressure generally justify closer surveillance, and a new symptom matters even when the last investigation was reassuring.

Practice

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Obstetrics and gynaecologyOriginal SBA

Persistent pressure at booking

A 34-year-old at 12 weeks has chronic hypertension and repeated blood pressures of 148/94 mmHg. She is asymptomatic, has normal baseline investigations and has no asthma or conduction disease. Which plan best matches NICE antenatal management?

Choose one answer, then submit
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Sources and review status5 sources · checked 7 Sept 2026 · clinical review pending+
Sources

Sources and review status

National guidance is shown before implementation-dependent detail. Typical adult dose examples remain subject to patient factors, contraindications and the live BNF or specialist protocol. Source check completed 7 Sept 2026; clinical approval remains outstanding.

  • NICE NG133: Hypertension in pregnancy recommendations
  • NHS: High blood pressure in pregnancy
  • Labetalol 100 mg tablets: current SmPC
  • Adalat LA 30 mg: prolonged-release nifedipine SmPC
  • Methyldopa 250 mg tablets: SmPC

Editorial contact: Doctor’s Passport editorial team. Source-check date is separate from clinical approval. Report a content problem · Content changes

Authoring stateComplete draftClinical stateAwaiting reviewJurisdictionUnited Kingdom

Preconception review is an opportunity to assess renal function, end-organ damage and the suitability of existing medicines. ACE inhibitors and angiotensin-receptor blockers require discussion of alternatives; if pregnancy occurs during their use, NICE advises stopping them preferably within two working days of notification and offering an appropriate replacement. Thiazide or thiazide-like diuretics also warrant specialist review. Do not stop all antihypertensives indiscriminately, because uncontrolled maternal pressure itself causes harm.

Non-severe hypertension is managed through a maternity plan that integrates blood-pressure control with surveillance for placental and maternal disease. A sustained reading of 140/90 mmHg or above is a treatment threshold, not the severe-emergency threshold. On medication the NICE target is 135/85 mmHg. In chronic hypertension, continuing an otherwise suitable existing medicine is reasonable unless sustained systolic pressure falls below 110 mmHg, diastolic below 70 mmHg, or symptomatic hypotension develops.

Labetalol is commonly chosen, but asthma, significant bradycardia or conduction disease can make it inappropriate. Nifedipine is an alternative; prescribe the exact formulation because modified-release products have different schedules and immediate-release treatment is not interchangeable with maintenance therapy. Methyldopa is another option but causes sedation and needs attention to liver disease and depressive illness. Treatment is titrated against measured response, with urgent inpatient management when pressure becomes severe.

Birth does not immediately remove vascular risk. Blood pressure often rises during the first postnatal days, and new pre-eclampsia may appear after discharge. Provide explicit symptom advice and a written monitoring and dose-adjustment plan. Breastfeeding usually permits appropriate antihypertensive therapy; enalapril is a NICE postnatal option with maternal renal and potassium monitoring. Long-term review should address persistent hypertension, cardiovascular risk and planning for subsequent pregnancy.

Key points

  • Hypertension means systolic pressure at least 140 mmHg or diastolic pressure at least 90 mmHg; either component can establish an abnormal result.
  • Hypertension present before pregnancy, at booking or before 20 weeks is usually chronic; new hypertension after 20 weeks without pre-eclampsia features is gestational.
  • For sustained non-severe hypertension, offer medication at 140/90 mmHg or higher and aim for approximately 135/85 mmHg on treatment.
  • Consider labetalol, use nifedipine if unsuitable, and methyldopa if both are unsuitable, incorporating previous response, contraindications and patient preference.
  • Chronic hypertension warrants aspirin 75–150 mg orally daily from 12 weeks until birth unless contraindicated.
  • Never use absent proteinuria alone to rule out pre-eclampsia; maternal organ dysfunction or uteroplacental dysfunction can fulfil the diagnosis.
  • Avoid routine birth before 37 weeks for otherwise uncomplicated hypertension below 160/110 mmHg; agree timing after 37 weeks with the senior obstetric team.
  • Measure blood pressure after birth, stop methyldopa within two days, and arrange medication review and a six-to-eight-week medical assessment.

Aetiology

01

Pre-existing vascular disease

Essential hypertension accounts for many chronic cases, while renal disease, endocrine disorders and vascular abnormalities may underlie earlier or difficult-to-control hypertension.

02

Pregnancy-associated hypertension

New hypertension after mid-pregnancy reflects altered maternal vascular adaptation; progression to placental and multisystem disease determines whether the later diagnosis becomes pre-eclampsia.

Pathophysiology

  1. 1
    Vascular resistance

    Persistent arteriolar constriction raises arterial pressure and increases cardiac workload, exposing maternal cerebral and other vascular beds to pressure-related injury.

  2. 2
    Physiological pressure fall

    Early pregnancy reduces systemic vascular resistance, so chronic hypertension may appear improved before blood pressure rises again later in gestation.

  3. 3
    Placental vulnerability

    Underlying vascular disease can impair placental perfusion, increasing the likelihood of fetal growth restriction and superimposed pre-eclampsia despite apparently satisfactory maternal symptom control.

Clinical features and red flags

Antenatal timing

A documented pre-pregnancy diagnosis or raised pressure before 20 weeks supports chronic hypertension even if subsequent readings temporarily improve.

New late-pregnancy pressure

Hypertension after 20 weeks requires assessment for proteinuria, organ dysfunction and placental insufficiency before calling it isolated gestational hypertension.

Progressive symptom burden

New headache, visual disturbance, nausea with upper abdominal pain or breathlessness should trigger reassessment regardless of a previous uncomplicated label.

Treatment intolerance

Dizziness, wheeze, marked fatigue or a slow pulse can indicate medicine-related harm and should prompt examination and supervised adjustment.

Red flags requiring action

  • Severe headache, flashing lights, epigastric pain, new breathlessness or reduced fetal movements require immediate maternity review for pre-eclampsia or placental compromise.
  • Any blood pressure at or above 160 systolic or 110 diastolic needs urgent reassessment and escalation; do not wait for a routine follow-up appointment.
  • Oliguria, falling platelets, rising creatinine or transaminases, pulmonary oedema or a seizure signifies possible multisystem disease.

Investigations

  1. 01
    Repeated standardised blood pressureFirst step
    Why
    Confirm persistence and identify a severe reading that changes urgency.
    Interpretation and limitations
    Use either systolic or diastolic threshold; home measurements can assist an agreed plan but must not postpone review of severe clinic values.
  2. 02
    Urine dipstick followed by protein quantification
    Why
    Look for renal involvement and establish a useful baseline.
    Interpretation and limitations
    A positive dipstick prompts protein:creatinine or albumin:creatinine measurement; proteinuria must be interpreted with symptoms, blood pressure and other organ findings.
  3. 03
    Full blood count, creatinine and liver tests
    Why
    Detect evolving thrombocytopenia, kidney injury or hepatic involvement.
    Interpretation and limitations
    A normal initial panel does not guarantee stability; repeat according to the hypertensive category and any clinical change.
  4. 04
    Fetal growth, fluid and umbilical artery Doppler ultrasound
    Why
    Assess growth and placental function when hypertension increases fetal risk.
    Interpretation and limitations
    For chronic hypertension NICE specifies scans at 28, 32 and 36 weeks; gestational-hypertension schedules depend on findings and clinical indication.
  5. 05
    PlGF-based testing for suspected preterm pre-eclampsia
    Why
    Add placental information when clinical assessment raises suspicion before term.
    Interpretation and limitations
    Use within the approved gestational range and alongside clinical assessment, generally from 20 to 36+6 weeks; it does not replace emergency assessment or independently determine birth.

Differential diagnosis

01

White-coat elevation

Anxiety or measurement error can raise a clinic reading; repeated validated measurements help clarify the pattern while severe values still require prompt assessment.

02

Pre-eclampsia

Hypertension accompanied by new proteinuria, maternal organ dysfunction or uteroplacental dysfunction requires the pre-eclampsia pathway rather than an isolated gestational-hypertension label.

03

Secondary hypertension

Renal, endocrine and vascular causes become especially relevant with young onset, resistant pressure, hypokalaemia or a history suggesting an established systemic disorder.

Management

01Initial assessmentClassify hypertension and assess current riskFirst stepA raised antenatal blood pressure is confirmed on appropriate repeat measurement.+
  1. 1Review prior readings, gestation, medication exposure, secondary causes and previous hypertensive pregnancy complications.
  2. 2Ask actively about neurological, respiratory, upper abdominal and fetal-movement symptoms, and obtain urine and baseline blood tests.
  3. 3Refer newly identified gestational hypertension for specialist assessment and provide an explicit review interval and emergency contact route.
02Treatment selectionControl persistent pressure with pregnancy-compatible therapyBlood pressure remains at least 140/90 mmHg without a severe emergency.+
  1. 1Discuss labetalol, then nifedipine or methyldopa when the preceding choices are unsuitable, using comorbidity and prior response to guide selection.
  2. 2EscalationSet a target around 135/85 mmHg and arrange measurements after initiation or escalation rather than issuing an open-ended repeat prescription.
  3. 3For chronic hypertension prescribe indicated aspirin prevention and organise fetal growth surveillance without implying that pressure control prevents every placental complication.
03Postnatal transitionProvide continuity through the postpartum pressure riseThe patient has given birth and needs a safe discharge treatment plan.+
  1. 1Check pressure daily for the first two days and at least once on days three to five, adding measurements after treatment changes.
  2. 2Stop methyldopa within two days and substitute if needed; tailor ongoing medicines to breastfeeding, renal function and blood-pressure response.
  3. 3EscalationDocument thresholds for escalation and dose reduction, arrange early review if still treated and offer a medical review at six to eight weeks.
Key medicines and prescribing safety4 treatments · regimens, roles and cautions+
A NICE-preferred option for persistent chronic or gestational hypertension when beta-blockade is appropriate.

Labetalol oral maintenance

A product-supported starting regimen is 100 mg orally twice daily, increased according to response; outpatient increments may be 100 mg twice daily at weekly intervals, with faster supervised inpatient titration when necessary.

Avoid with asthma or significant bradycardia, heart block or decompensated heart failure; assess maternal symptoms and neonatal beta-blockade risk.

Provides an alternative when labetalol is unsuitable or not tolerated.

Nifedipine prolonged release

One product-specific maintenance option is Adalat LA 30 mg orally once daily, titrated by the maternity prescriber to measured response within that product's authorised range.

Specify brand and release formulation, swallow whole, assess headache or hypotension and check current pregnancy wording and drug interactions.

An alternative when labetalol and nifedipine are unsuitable for antenatal pressure control.

Methyldopa

Start 250 mg orally two or three times daily for two days; adjust at intervals of at least two days, up to 3 g daily, and stop within two days after birth.

Check liver disease, depression, sedation and renal impairment; investigate unexplained jaundice or anaemia and make a postnatal replacement plan.

Pre-eclampsia prophylaxis for the high-risk group defined by chronic hypertension.

Aspirin in chronic hypertension

Prescribe 75–150 mg orally once each day beginning at 12 weeks and continuing until birth, after checking contraindications.

Complications

01

Maternal vascular injury

Severe uncontrolled pressure can produce intracranial haemorrhage, cardiac failure and other end-organ injury, sometimes before the patient reports prominent symptoms.

02

Fetal compromise

Placental dysfunction may cause restricted growth, abnormal Dopplers or a need for medically indicated preterm birth, with consequences dependent on gestational age.

03

Future cardiovascular disease

A hypertensive pregnancy identifies increased later cardiovascular risk and should lead to continuing blood-pressure, lifestyle and cardiometabolic assessment after obstetric care ends.

Monitoring and follow-up

  • For controlled chronic hypertension consider additional appointments every two to four weeks, increasing to weekly when control is poor.
  • In gestational hypertension monitor blood pressure and urine once or twice weekly, with weekly blood count, renal and liver tests, adjusted to clinical status.
  • Record growth-scan findings together with maternal trends so that worsening placental function is not lost between separate clinic letters.
  • Reassess dizziness or low readings before escalating treatment solely on an isolated earlier measurement.
  • Ensure persistent postnatal hypertension enters a long-term primary-care pathway and that future pregnancy plans include medication review.

Special situations

One component is sufficient

A systolic pressure of 165 with a diastolic of 90 is still severe hypertension and must not be averaged into a reassuring category.

Baseline protein matters

Pre-existing renal protein loss can complicate interpretation later; a recorded early baseline helps assess superimposed disease without relying on protein change alone.

Pressure and placenta differ

Good antihypertensive response reduces maternal pressure-related danger but does not prove that placental growth and perfusion are normal.

Postnatal treatment changes

An ACE inhibitor can be inappropriate during pregnancy yet suitable after birth with appropriate breastfeeding and maternal biochemical assessment.

Common pitfalls

  1. 01

    Labelling every new raised pressure after 20 weeks as pre-eclampsia without examining the diagnostic criteria.

  2. 02

    Using the non-pregnant threshold of 180/120 mmHg to decide whether antenatal hypertension is an emergency.

  3. 03

    Stopping every antihypertensive at a positive pregnancy test instead of arranging a prompt replacement for unsuitable agents.

  4. 04

    Treating a normal urine dipstick as permission to ignore severe headache or laboratory deterioration.

  5. 05

    Discharging on methyldopa indefinitely without postnatal review and an explicit alternative when medication remains necessary.

Check aspirin hypersensitivity, clinically significant bleeding and interacting anticoagulation; aspirin does not treat severe blood pressure.