Hypertension in Pregnancy

Overview – Hypertension in Pregnancy

Hypertension in pregnancy refers to elevated blood pressure (≥140/90 mmHg) occurring during or before pregnancy and is a key contributor to maternal and perinatal morbidity and mortality. It can range from chronic hypertension to gestational hypertension, and severe forms like pre-eclampsia and eclampsia. Prompt diagnosis, close monitoring, and appropriate treatment are essential to ensure maternal and fetal safety.

Definition

• Blood pressure ≥140/90 mmHg on two or more separate occasions
• Four clinical classifications:
  • Chronic Hypertension:
    → Present before pregnancy or before 20 weeks gestation
    → Associated with increased risk of developing gestational hypertension or pre-eclampsia
  • Gestational Hypertension:
    → Occurs after 20 weeks gestation
    → No proteinuria or signs of organ dysfunction
  • Pre-Eclampsia (with or without chronic HTN):
    → Hypertension + signs of maternal organ dysfunction
    → Affects kidneys (proteinuria, raised creatinine), liver (elevated LFTs, RUQ pain), brain (headaches, clonus), hematological system (thrombocytopenia, haemolysis, DIC), or placenta (fetal growth restriction)
  • Eclampsia:
    → Pre-eclampsia complicated by generalised tonic-clonic seizures
    → Life-threatening emergency requiring urgent intervention

Gestational Hypertension

Risk Factors

• Primigravida (>80% of cases)
• First pregnancy with a new partner
• Diabetes mellitus
• Chronic kidney disease
• Obesity
• Extremes of maternal age (<18 or >35 years)
• Intrauterine growth restriction (IUGR)
• Oligohydramnios
• Multiple gestation

Investigations

• Full clinical exam including BMI and neurological assessment
• Fetal ultrasound and non-stress test
• Bloods: FBC, UECs, LFTs
• 24-hour urine collection (albumin:creatinine ratio)

Management

• Antihypertensives:
  • First-line: Labetalol, Nifedipine XR, Methyldopa
  • Severe: IV Hydralazine
• Avoid: ACE inhibitors, angiotensin receptor blockers, diuretics, prazosin, atenolol

Complications

• Maternal: renal/liver dysfunction, eclampsia, DIC, HELLP syndrome, stroke, pulmonary oedema
• Fetal: IUGR, prematurity, placental abruption

Pre-Eclampsia and Eclampsia

Aetiology

• Defective placental development and invasion of spiral arterioles
• Risk factors: Primigravida, older maternal age, family history, diabetes, chronic HTN, molar pregnancy, multiple gestation

Pathogenesis

• Placental ischaemia leads to widespread vasoconstriction → hypertension
• Severe disease may result in infarction, multiorgan failure, and seizures (eclampsia)

Clinical Features

• Affects 5–10% of pregnancies
• Symptoms:
  • Headaches, visual disturbances
  • RUQ/epigastric pain
  • Pitting oedema
  • Purpura (HELLP syndrome)
  • Seizures (eclampsia)

Diagnosis

• Symptom screening: headache, vision changes, oedema, rashes
• BP measurement ≥140/90
• Urine dipstick (proteinuria)
• Blood tests: FBC, UECs, LFTs
• Ultrasound for fetal assessment

Management

• Hospital admission and 4-hourly monitoring
• Serial bloods and fetal USS
• Medications:
  • Antenatal corticosteroids (betamethasone)
  • Calcium channel blockers (nifedipine), magnesium sulfate infusion
  • Beta-blockers (labetalol)
• Definitive management = delivery of the fetus
• Eclampsia protocol:
  1. Stabilise with magnesium sulfate (do not use anticonvulsants)
  2. Immediate delivery
  3. ICU/HDU recovery monitoring for ≥4 days post-normalisation of BP

Complications

• IUGR
• HELLP syndrome (haemolysis, elevated liver enzymes, low platelets)
• DIC
• Liver or renal failure
• Placental abruption
• Cerebral haemorrhage
• Aspiration pneumonia
• Death

Prognosis

• Eclampsia is rare with adequate management but carries a ~20% mortality risk if untreated

Summary – Hypertension in Pregnancy

Hypertension in pregnancy includes chronic, gestational, and pre-eclamptic states, all of which carry significant maternal and fetal risks. Pre-eclampsia and eclampsia are severe variants that require urgent management. Early diagnosis, continuous monitoring, and timely delivery are critical. For more, visit our Obstetrics Overview page.