Diagnosis and spectrum
Definition (Isshp / NICE Ng133)
- New-onset hypertension (≥140/90) after 20 weeks gestation
PLUS one or more of:
- Proteinuria — urine ACR ≥8 mg/mmol or PCR ≥30 mg/mmol, or ≥1+ on dipstick confirmed by lab
- Maternal organ dysfunction: AKI (creatinine ≥90 μmol/L), liver involvement (ALT >40), neurological (eclampsia, severe headaches, visual disturbance), haematological (platelets <150)
- Uteroplacental dysfunction: fetal growth restriction
Severe Pre-eclampsia
- BP ≥160/110
- Severe proteinuria, AKI, severe hepatic dysfunction, HELLP syndrome, eclampsia, pulmonary oedema
Hellp Syndrome
- Haemolysis, Elevated Liver enzymes, Low Platelets
- A severe form of pre-eclampsia, often with rapid AKI
Related Syndromes
- Gestational hypertension: new BP elevation after 20 weeks without proteinuria/organ dysfunction
- Chronic hypertension: present before 20 weeks or before pregnancy
- Superimposed pre-eclampsia: new proteinuria or organ dysfunction in pre-existing hypertension or CKD
Kidney-specific Features
- AKI in up to 20% of severe pre-eclampsia
- Nephrotic-range proteinuria possible
- Glomerular endotheliosis on biopsy — endothelial swelling, loss of fenestrations, subendothelial fibrin
- Differential includes acute fatty liver of pregnancy, pregnancy-associated TMA/aHUS, lupus flare, AKI from other causes
Prediction and prevention
RISK FACTORS — high risk (any one):
- Previous pre-eclampsia
- Pre-existing CKD
- Autoimmune disease (SLE, antiphospholipid syndrome)
- Type 1 or type 2 diabetes
- Chronic hypertension
MODERATE RISK (any two):
- First pregnancy
- Age ≥40
- Pregnancy interval >10 years
- BMI ≥35 at booking
- Family history of pre-eclampsia
- Multiple pregnancy
First-trimester Screening
- Combined screening (maternal factors + uterine artery PI + MAP + PlGF) is more accurate than NICE risk factors alone
- Increasingly available in UK fetal medicine units
Prevention
- ASPIRIN 150 mg from before 16 weeks until 36 weeks — for any high-risk factor or two or more moderate risks (NICE NG133)
- ASPRE trial: aspirin reduces preterm pre-eclampsia by 62%
- Calcium 1 g/day if dietary intake low — useful particularly in low-calcium-intake populations
- Lifestyle: weight optimisation pre-conception, exercise
- Do NOT prescribe LMWH routinely for pre-eclampsia prevention
Angiogenic Testing (NICE Dg23)
- sFlt-1/PlGF ratio (Roche Elecsys) or PlGF alone (Triage/DELFIA, Quidel)
- Use between 20+0 and 36+6 weeks in women with suspected pre-eclampsia
- Ratio ≤38: pre-eclampsia in next 7 days very unlikely (high NPV)
- Ratio >38: pre-eclampsia likely; intensify monitoring and consider admission
- Reduces unnecessary admission and improves timing of delivery
Kidney Vitality is a daily multivitamin developed by a UK Consultant Nephrologist using renal nutrition principles. It contains no added potassium, magnesium, phosphorus or iron, and no herbal blends. See the formulation.
Management
ANTIHYPERTENSIVES — first-line in pregnancy:
- Labetalol (oral or IV)
- Nifedipine MR
- Methyldopa (lower preference now)
- AVOID in pregnancy: ACE inhibitors, ARBs, direct renin inhibitors, spironolactone
- BP targets: aim <135/85 (CHIPS trial supports tighter control without increased fetal risk)
Magnesium Sulphate
- For severe pre-eclampsia and prevention/treatment of eclampsia
- 4 g IV bolus over 5-10 min, then 1 g/hour
- Monitor for toxicity (loss of reflexes, respiratory depression) especially if eGFR low — reduce dose
Fluid Balance
- Restrict IV fluids to ~80 ml/h
- Pulmonary oedema is a major cause of maternal mortality
- Strict input-output charting
Timing Of Delivery
- Term pre-eclampsia (≥37 weeks): deliver
- Late preterm (34-37): individualised
- <34 weeks: aim to prolong if maternal and fetal condition allow; antenatal corticosteroids for fetal lung maturity; deliver for maternal or fetal indication
Postpartum
- BP often rises in first 3-7 days postpartum — risk of stroke and eclampsia continues
- Continue antihypertensives; transition to enalapril, ramipril, atenolol (avoid in breastfeeding if possible; labetalol, nifedipine and enalapril are breastfeeding-safe)
- Magnesium for 24h post-delivery in severe pre-eclampsia
- Watch for HELLP and AKI in the puerperium
- Be alert to pregnancy-associated aHUS if AKI worsens after delivery — refer urgently to nephrology
Postnatal kidney follow-up and long-term risk
Every Woman After Pre-eclampsia
- BP check at 7-10 days and 6 weeks postpartum
- Urine ACR at 6-12 weeks
- Persistent proteinuria, hypertension or reduced eGFR → refer to nephrology
- If pre-existing CKD — joint renal/obstetric review for future planning
When To Investigate Further
- ACR remains elevated at 3 months
- eGFR has not recovered
- Atypical features (low complement, active sediment, persistent TMA)
- Consider biopsy, autoimmune screen, complement work-up (aHUS), APS screen
Long-term Risk
- ~2× lifetime risk of hypertension
- ~2× risk of stroke and ischaemic heart disease
- ~5× risk of recurrent pre-eclampsia in future pregnancy (especially if early-onset or severe)
- ~4× risk of ESKD in some cohort studies
- Increased risk of type 2 diabetes
Lifelong Surveillance
- Annual BP
- Annual weight, lipids, HbA1c, ACR
- Lifestyle counselling: smoking cessation, exercise, Mediterranean diet, weight
- Statin if cardiovascular risk meets QRISK threshold
Future Pregnancy Planning
- Pre-pregnancy counselling, ideally in a joint maternal-medicine clinic
- Start aspirin 150 mg from <16 weeks
- Tight BP control before conception
- Switch ACE/ARB to pregnancy-safe alternatives BEFORE conception
- Consider PlGF / sFlt-1 surveillance in pregnancy
KEY MESSAGE: pre-eclampsia is not over at delivery — it is a lifelong cardiovascular and kidney risk factor that deserves structured follow-up.
