How can I conduct pre‑eclampsia problem‑based learning in primary care for a pregnant woman in her first or second trimester who has risk factors such as nulliparity, chronic hypertension, pre‑gestational diabetes, renal disease, obesity, or a prior episode of pre‑eclampsia?

Conducting Pre-Eclampsia Problem-Based Learning in Primary Care

Structure your pre-eclampsia problem-based learning session around the PRECOG guideline's three-phase algorithmic approach: early risk assessment (before 20 weeks), risk stratification with specialist referral criteria, and systematic post-20-week surveillance—this evidence-based framework directly addresses the maternal and perinatal mortality that occurs in 46% of maternal and 65% of fetal deaths when risk factors are missed 1.

Phase 1: Early Pregnancy Risk Assessment (Before 20 Weeks)

Begin your PBL case by having learners systematically identify risk factors at the first prenatal visit. The PRECOG guideline provides quantified relative risks that should guide your teaching 1:

High-Priority Risk Factors (Require Immediate Specialist Referral)

Present cases where learners must recognize these conditions that mandate specialist input before 20 weeks 1:

• Previous pre-eclampsia (RR 7.19) - highest single historical risk factor
• Pre-existing hypertension or booking diastolic BP ≥90 mm Hg (RR 5.1) 2
• Pre-existing diabetes (RR 3.56)
• Pre-existing renal disease or booking proteinuria (≥+ on multiple occasions or ≥300 mg/24h)
• Antiphospholipid antibodies (RR 9.72) - highest overall risk
• Multiple pregnancy (RR 2.93)
• Any two other factors from the moderate-risk list below

Moderate-Risk Factors to Document

Structure case scenarios around identifying 1:

• Nulliparity (RR 2.91)
• Age ≥40 years (RR 1.68-1.96)
• BMI ≥35 (RR 1.55)
• Family history of pre-eclampsia in mother or sister (RR 2.90)
• Booking diastolic BP ≥80 mm Hg (even if <90)
• ≥10 years since last pregnancy

Phase 2: Post-20 Week Surveillance Protocol

Design your PBL cases to teach the systematic assessment required at every prenatal visit after 20 weeks 1. This is where most preventable deaths occur due to failure to recognize warning signs 1.

At Every Assessment, Learners Must Check For:

New hypertension (diastolic BP ≥90 mm Hg in women with BP <90 before 20 weeks) 1

New proteinuria (≥+ on dipstick, protein:creatinine ratio ≥30 mg/mmol, or ≥300 mg/24h) 1

Warning symptoms 1:

• Headache or visual disturbances
• Epigastric pain or vomiting
• Reduced fetal movements
• Small for gestational age infant

Blood Pressure Measurement Technique

The USPSTF guideline specifies exact technique—incorporate this into your PBL skills station 3:

• Patient relaxed for 5 minutes before measurement
• Sitting position with legs uncrossed, back supported
• Arm at level of right atrium
• Use large cuff if upper arm circumference ≥33 cm
• Never measure in left lateral position (falsely lowers readings) 3
• Confirm elevated readings with repeated measurements

Phase 3: Risk Stratification and Referral Decisions

Create decision-making scenarios where learners must determine appropriate care level. The PRECOG guideline provides a two-tiered monitoring system 1:

Immediate Specialist Referral Criteria

Present cases requiring urgent action when patients develop 1:

• New hypertension (BP ≥140/90) plus new proteinuria = pre-eclampsia diagnosis
• Superimposed pre-eclampsia (new features in context of pre-existing hypertension or proteinuria)
• Any warning symptoms with hypertension or proteinuria

Enhanced Community Monitoring

For high-risk women without active disease, teach the intensified surveillance schedule between 24-32 weeks and 32 weeks to delivery 1.

Prevention Strategies for High-Risk Cases

Incorporate aspirin prophylaxis decision-making into your PBL scenarios 3, 4, 5:

• Aspirin 150 mg at bedtime (not 81 mg as in older guidelines) starting at 11-14+6 weeks 4
• Continue until 36 weeks, delivery, or pre-eclampsia diagnosis
• Only for women at high risk (≥1:100 risk for preterm pre-eclampsia)
• Do not prescribe aspirin to all pregnant women 4

For women with low calcium intake (<800 mg/day), consider calcium supplementation (1.5-2 g elemental calcium daily) 4.

Key Teaching Points for Clinical Context

Common Pitfalls to Emphasize

Failure to act on risk factors at booking accounts for nearly half of preventable deaths 1. Structure cases where learners must recognize that:

• A single risk factor (like nulliparity or obesity) requires documentation and heightened surveillance
• Two moderate risk factors = specialist referral before 20 weeks 1
• Chronic hypertension has 16% rate of developing pre-eclampsia 2—these women need aspirin and close monitoring

Definitions That Matter

Pre-eclampsia requires both 1:

• New hypertension (≥140/90) at or after 20 weeks, AND
• Quantified proteinuria (≥300 mg/24h)
• Confirmed if resolves after delivery

Superimposed pre-eclampsia = development of pre-eclampsia features in women with pre-existing hypertension or proteinuria 1—this is particularly dangerous and easily missed.

Practical PBL Case Structure

Design your cases with progressive complexity:

1. Case 1: 32-year-old nulliparous woman, BMI 37 → Learners identify two risk factors, discuss enhanced monitoring
2. Case 2: 28-year-old with previous pre-eclampsia at 34 weeks → Learners must recommend specialist referral before 20 weeks and aspirin prophylaxis
3. Case 3: 35-year-old with chronic hypertension presents at 26 weeks with BP 150/95 and trace proteinuria → Learners must recognize superimposed pre-eclampsia risk and arrange urgent assessment
4. Case 4: 42-year-old with headaches at 32 weeks, BP 145/92 → Learners must systematically assess for pre-eclampsia features and determine referral urgency

The algorithmic approach from PRECOG provides the framework that reduces the 46% of maternal deaths and 65% of fetal deaths that are preventable with proper recognition and response 1. Your PBL session should drill this systematic approach until it becomes automatic clinical practice.