Kindly make simple notes on ACOG AND NICE guidelines on hypertensive disorders of pregnancy - also add quiz based question on this.
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ACOG NICE guidelines hypertensive disorders of pregnancy 2024 2025 key recommendations
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https://pmc.ncbi.nlm.nih.gov/articles/PMC10941709
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Hypertensive Disorders of Pregnancy
ACOG & NICE Guidelines - Simple Notes + Quiz
PART 1: CLASSIFICATION (ACOG & NICE)
Both ACOG and NICE use similar classifications, with minor differences in thresholds.
| Category | Definition |
|---|---|
| Chronic Hypertension | HTN present before pregnancy or diagnosed before 20 weeks gestation |
| Gestational Hypertension | New-onset HTN after 20 weeks, NO proteinuria/end-organ damage; resolves by 12 weeks postpartum |
| Preeclampsia | Gestational HTN + proteinuria OR end-organ damage |
| Eclampsia | Preeclampsia + new-onset seizures |
| Chronic HTN with superimposed preeclampsia | Pre-existing HTN + new proteinuria or worsening end-organ damage after 20 weeks |
PART 2: DIAGNOSTIC THRESHOLDS
Blood Pressure Criteria
- HTN defined as: SBP ≥ 140 mmHg AND/OR DBP ≥ 90 mmHg on two readings at least 4 hours apart
- Severe-range HTN: SBP ≥ 160 mmHg AND/OR DBP ≥ 110 mmHg (can be confirmed within 15 minutes if severe)
Proteinuria (for preeclampsia diagnosis)
- 24-hour urine protein > 300 mg
- Protein:creatinine ratio > 0.3
- Dipstick: 2+ or more (only if other methods unavailable)
Preeclampsia WITHOUT Proteinuria - ACOG allows diagnosis if any end-organ damage present:
- Platelets < 100 x 10⁹/L (thrombocytopenia)
- Creatinine > 1.1 mg/dL or doubling of creatinine
- Liver transaminases ≥ 2x upper limit of normal
- Pulmonary edema
- New-onset headache not relieved by analgesics
- Visual disturbances
NICE difference: NICE does NOT require end-organ damage to diagnose preeclampsia without proteinuria - proteinuria remains the primary marker in NICE. NICE also endorses PlGF (placental growth factor)-based testing to rule out preeclampsia; ACOG does not routinely recommend this.
PART 3: SEVERE FEATURES OF PREECLAMPSIA (ACOG)
Preeclampsia is classified as "with severe features" if any of the following are present:
- Severe-range BP (SBP ≥ 160 or DBP ≥ 110 on 2 readings ≥ 4 hr apart)
- Platelets < 100 x 10⁹/L
- Creatinine > 1.1 mg/dL or doubling
- LFTs ≥ 2x normal + severe RUQ/epigastric pain
- Pulmonary edema
- New-onset headache unresponsive to analgesics
- Visual disturbances
- HELLP syndrome (Hemolysis, Elevated Liver enzymes, Low Platelets)
NICE uses the term "severe hypertension" (BP ≥ 160/110) rather than "severe features" as a separate category, but the management approach is similar.
PART 4: ANTIHYPERTENSIVE TREATMENT
When to Start Treatment
| Guideline | Threshold to Start |
|---|---|
| ACOG | Severe-range BP only (≥ 160/110 mmHg); non-severe BP (140-159/90-109) does NOT require treatment unless there is chronic HTN requiring meds |
| NICE | Lower threshold: treat if BP ≥ 150/100 mmHg consistently |
Key difference: NICE treats at a lower BP (150/100), while ACOG only mandates treatment at 160/110.
BP Targets
| Guideline | Target BP |
|---|---|
| ACOG | < 160/110 (severe-range prevention); non-severe range is permissible |
| NICE | < 135/85 mmHg (tighter control across all HDP categories) |
First-Line Antihypertensives in Pregnancy (Both Guidelines)
| Drug | Route | Notes |
|---|---|---|
| Labetalol | IV (acute) / Oral (chronic) | First-line for acute severe HTN (ACOG + NICE) |
| Nifedipine | Oral (IR or extended-release) | Oral first-line; do NOT use sublingual |
| Hydralazine | IV | Alternative for acute severe HTN |
| Methyldopa | Oral | Safe in pregnancy; preferred in some settings (NICE includes this) |
Contraindicated: ACE inhibitors, ARBs (teratogenic - fetal renal anomalies, growth restriction)
PART 5: SEIZURE PROPHYLAXIS - MAGNESIUM SULFATE
Both ACOG and NICE recommend magnesium sulfate (MgSO₄) for:
- Prevention of eclampsia in preeclampsia with severe features
- Treatment of eclamptic seizures
ACOG MgSO₄ Protocol:
- Loading dose: 4-6 g IV over 15-20 minutes
- Maintenance: 1-2 g/hour IV infusion
- Monitor for toxicity: urine output, reflexes, respiratory rate, serum Mg levels
NICE difference: NICE recommends MgSO₄ in severe preeclampsia and notes it should be considered if birth is planned within 24 hours for women with severe hypertension.
MgSO₄ Toxicity - Antidote: Calcium gluconate 1 g IV
PART 6: PREVENTION OF PREECLAMPSIA - LOW-DOSE ASPIRIN
Both ACOG and NICE recommend low-dose aspirin (LDA) for high-risk patients.
Who Gets Aspirin?
ACOG - High Risk (any 1 factor):
- Prior preeclampsia
- Multifetal gestation
- Chronic HTN, diabetes, renal disease
- Autoimmune disease (SLE, antiphospholipid syndrome)
- Prior preterm birth < 34 weeks
ACOG - Moderate Risk (≥ 2 factors):
- Nulliparity, BMI > 30, age ≥ 35, family history of preeclampsia
NICE - Recommends aspirin if ≥ 1 high-risk OR ≥ 2 moderate-risk factors (similar to ACOG)
Aspirin Dose & Timing
- ACOG: 81 mg/day, started 12-28 weeks (ideally before 16 weeks), continued until delivery
- NICE: 75-150 mg/day, started from 12 weeks
PART 7: DELIVERY TIMING (ACOG)
| Condition | Delivery Timing |
|---|---|
| Gestational HTN or preeclampsia without severe features | 37 weeks |
| Preeclampsia with severe features (stable) | 34 weeks |
| Unstable preeclampsia with severe features / HELLP | Immediate delivery after stabilization |
| Chronic HTN - controlled, no meds | 38-39+6 weeks |
| Chronic HTN - controlled on meds | 37-39+6 weeks |
| Chronic HTN - poorly controlled on meds | 36-37+6 weeks |
| Superimposed preeclampsia with severe features + abnormal labs | 34 weeks |
NICE recommends individualized timing; general guidance aligns with ACOG but emphasizes multidisciplinary decision-making.
PART 8: POSTPARTUM MANAGEMENT
- Continue antihypertensives postpartum if BP remains ≥ 150/100 mmHg
- Monitor BP for at least 72 hours after delivery (risk of late-onset postpartum preeclampsia)
- NICE recommends postpartum BP monitoring until 6-8 weeks
- ACOG states NSAIDs are safe for pain control in postpartum HTN patients (does not significantly worsen BP)
- Women with prior preeclampsia have 2x risk of future hypertension and cardiovascular disease - long-term follow-up is needed
- ACOG/AHA recognizes prior preeclampsia as an established cardiovascular risk factor
QUIZ SECTION - Hypertensive Disorders of Pregnancy
Q1. A 28-year-old primigravida at 32 weeks gestation presents with BP of 155/98 mmHg on two readings 6 hours apart, 2+ proteinuria on dipstick, and mild headache. Her platelets are 145 x 10⁹/L and creatinine is 0.8 mg/dL. What is the most likely diagnosis?
- A) Chronic hypertension
- B) Gestational hypertension
- C) Preeclampsia without severe features
- D) Preeclampsia with severe features
Answer: C - BP is in non-severe range (< 160/110), proteinuria is present, end-organ markers are normal. This is preeclampsia WITHOUT severe features.
Q2. According to ACOG, at what blood pressure should antihypertensive therapy be URGENTLY started?
- A) ≥ 140/90 mmHg
- B) ≥ 150/100 mmHg
- C) ≥ 160/110 mmHg
- D) ≥ 170/110 mmHg
Answer: C - ACOG mandates urgent treatment only at severe-range BP (≥ 160/110). NICE has a lower threshold (150/100).
Q3. A patient with preeclampsia develops a generalized tonic-clonic seizure. What is the FIRST-line treatment?
- A) Diazepam IV
- B) Phenytoin IV
- C) Magnesium sulfate IV
- D) Lorazepam IV
Answer: C - MgSO₄ is the drug of choice for eclamptic seizures per both ACOG and NICE. Loading dose is 4-6 g IV over 15-20 minutes.
Q4. Which of the following is a contraindicated antihypertensive in pregnancy?
- A) Labetalol
- B) Nifedipine
- C) Enalapril
- D) Methyldopa
Answer: C - ACE inhibitors (enalapril) and ARBs are teratogenic and contraindicated in pregnancy. They cause fetal renal malformations and growth restriction.
Q5. A 34-year-old with preeclampsia WITHOUT severe features reaches 37 weeks gestation. What does ACOG recommend?
- A) Continue expectant management until 40 weeks
- B) Deliver at 37 weeks
- C) Deliver only if BP worsens
- D) Deliver at 34 weeks
Answer: B - ACOG recommends delivery at 37 weeks for gestational HTN or preeclampsia without severe features.
Q6. According to NICE (but NOT ACOG), which biomarker test is recommended to help RULE OUT preeclampsia?
- A) Uric acid
- B) Fibronectin
- C) Placental growth factor (PlGF)
- D) Beta-hCG
Answer: C - NICE endorses PlGF-based testing to help rule out preeclampsia. ACOG does not routinely recommend this, citing a low positive predictive value (79% of screen-positive PlGF patients do not develop HDP).
Q7. Magnesium sulfate toxicity occurs. Which of the following is the correct antidote?
- A) Flumazenil
- B) Protamine sulfate
- C) Calcium gluconate 1 g IV
- D) Naloxone
Answer: C - Calcium gluconate 1 g IV is the antidote for MgSO₄ toxicity.
Q8. A patient with chronic hypertension on oral labetalol has well-controlled BP throughout pregnancy. According to ACOG, at what gestational age should she be delivered?
- A) 34-35 weeks
- B) 36-37+6 weeks
- C) 37-39+6 weeks
- D) 40+ weeks only
Answer: C - For chronic HTN controlled on medications, ACOG recommends delivery at 37-39+6 weeks.
Q9. Low-dose aspirin for preeclampsia prevention should ideally be started by:
- A) 8 weeks gestation
- B) Before 16 weeks gestation (ACOG) / From 12 weeks (NICE)
- C) 24-28 weeks
- D) After the anatomy scan at 20 weeks
Answer: B - ACOG recommends initiating aspirin between 12-16 weeks (ideally before 16 weeks); NICE recommends from 12 weeks gestation.
Q10. Which of the following is NOT a severe feature of preeclampsia according to ACOG?
- A) Pulmonary edema
- B) Serum creatinine 1.3 mg/dL (from baseline of 0.6 mg/dL)
- C) Platelets 130 x 10⁹/L
- D) Persistent severe epigastric pain with elevated LFTs
Answer: C - Thrombocytopenia is defined as platelets < 100 x 10⁹/L for it to be a severe feature. Platelets of 130 are not in the severe range. All other options meet ACOG severe feature criteria.
Quick Reference Summary Table
| Feature | ACOG | NICE |
|---|---|---|
| HTN definition | ≥ 140/90 on 2 readings, 4 hr apart | ≥ 140/90 on 2 readings |
| Start treatment | ≥ 160/110 | ≥ 150/100 |
| BP target | < 160/110 | < 135/85 |
| PlGF testing | Not recommended | Recommended |
| Aspirin dose | 81 mg/day | 75-150 mg/day |
| Aspirin start | 12-28 wks (ideally < 16 wks) | From 12 weeks |
| MgSO₄ | Severe features | Severe preeclampsia |
| Delivery - no severe features | 37 weeks | Individualized (~37 wks) |
| Delivery - severe features (stable) | 34 weeks | 34 weeks |
| Postpartum monitoring | 72 hrs minimum | 6-8 weeks |
Sources: Braunwald's Heart Disease 9e (ETABLE 92.1, ACOG Classification); Creasy & Resnik's Maternal-Fetal Medicine; PMC10941709 (ACOG review); NICE Guideline NG133; Curr Hypertens Rep 2020 (International Guideline Comparison)
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