What is the prevention strategy for a woman with a history of two previous episodes of preeclampsia who desires another pregnancy?

Prevention Strategy for Recurrent Preeclampsia

For a woman with two prior episodes of preeclampsia planning another pregnancy, initiate low-dose aspirin 100-162 mg daily starting before 16 weeks gestation (ideally at 12 weeks) and continue until 36-37 weeks, combined with calcium supplementation if dietary intake is low, along with preconception optimization and intensive prenatal monitoring. 1

Preconception Counseling and Risk Assessment

Before attempting pregnancy, this patient requires comprehensive evaluation given her high-risk status with two prior preeclampsia episodes 2:

• Assess for underlying medical conditions: Screen for chronic hypertension, diabetes, renal disease, and thrombophilias that may have contributed to prior preeclampsia 2, 3
• Review prior pregnancy details: Document gestational age at onset, severity, presence of fetal growth restriction, and any maternal end-organ damage from previous episodes, as early-onset disease (<34 weeks) carries higher recurrence risk 2, 4
• Optimize maternal health: Achieve ideal body weight if BMI >35 kg/m², control any chronic hypertension or diabetes, and address modifiable cardiovascular risk factors before conception 1, 2
• Counsel on recurrence risk: Women with prior preeclampsia face substantially increased risk in subsequent pregnancies, with magnitude dependent on gestational age at prior onset and disease severity 2, 4

Primary Prevention: Aspirin Prophylaxis

Aspirin is the cornerstone of prevention and should be strongly recommended 1, 5:

• Dosing: 100-162 mg daily (some guidelines support up to 162 mg for highest-risk patients) 1
• Timing: Start before 16 weeks gestation, ideally at 12 weeks, as efficacy diminishes significantly if started after 16 weeks 1, 5, 3
• Duration: Continue until 36-37 weeks gestation or delivery 1
• Efficacy: Reduces preterm preeclampsia risk by approximately 62%, with greatest benefit for early-onset disease 1, 5

The evidence supporting aspirin is strongest for women with prior preeclampsia, particularly if complicated by early delivery or fetal growth restriction 5, 3.

Calcium Supplementation

Assess dietary calcium intake and supplement if deficient 1:

• Indication: Women consuming <600-800 mg calcium daily 1
• Dosing: 1.5-2 g elemental calcium daily (alternative lower dose of 1-1.2 g daily minimum may be considered) 1
• Mechanism: Reduces preeclampsia risk by 36-64% in calcium-deficient populations by reducing endothelial activation and hypertension 1, 5

Interventions to AVOID

Several interventions lack evidence or may cause harm 1, 2:

• Do NOT use vitamin C and E supplementation: May worsen outcomes 1
• Do NOT use fish oil supplementation: Shown ineffective for recurrent preeclampsia prevention 2
• Do NOT routinely prescribe antihypertensives prophylactically: No evidence for prevention in normotensive women with prior preeclampsia 2
• Low molecular weight heparin: Not recommended routinely even in high-risk populations unless specific thrombophilia or prior severe placental vasculopathy 3, 5

Lifestyle Modifications

Encourage evidence-based lifestyle interventions 1:

• Regular exercise: 50 minutes of aerobic, strength, and flexibility training 3 times weekly throughout pregnancy 1
• Normal diet without salt restriction: Avoid excessive water or salt restriction as this may induce low intravascular volume, which is counterproductive 1
• Weight management: Address obesity before conception if applicable 1

Intensive Prenatal Monitoring Protocol

Given the high recurrence risk, implement more frequent surveillance than standard prenatal care 2:

• First trimester ultrasound: Essential for accurate dating and establishing fetal number 2
• Baseline laboratory studies: Obtain complete metabolic panel, liver enzymes, complete blood count, uric acid, and 24-hour urine protein to establish baseline organ function 2
• Frequent prenatal visits: More frequent than standard care, with consideration for home blood pressure monitoring or nursing contacts between visits 2
• Serial fetal surveillance: If prior preeclampsia was complicated by fetal growth restriction, perform serial ultrasound evaluation of fetal growth and amniotic fluid volume 2
• Blood pressure monitoring: At every prenatal visit throughout pregnancy, with lower threshold for additional evaluation if elevated 2

Biomarker Screening Considerations

While promising, routine biomarker screening has limitations 6, 3:

• sFlt-1/PlGF ratio: FDA-approved for risk assessment but not routinely recommended solely to reduce morbidity 3, 7
• No single biomarker: Currently no clinically useful single biomarker for predicting recurrent preeclampsia 2
• Multiomics approaches: Under investigation but not yet ready for clinical implementation 6

Threshold for Hospitalization

Admit immediately if any of the following develop 2:

• Severe gestational hypertension (≥160/110 mmHg)
• Recurrent preeclampsia with any severity features
• Fetal growth restriction
• Non-reassuring fetal status

Long-term Cardiovascular Risk Counseling

Inform the patient about increased lifetime cardiovascular risk 3, 4:

• Women with prior preeclampsia have significantly increased risks of chronic hypertension, stroke, cardiovascular disease, diabetes, and renal dysfunction 3, 4
• Recommend lifelong medical follow-up to monitor blood pressure and manage cardiovascular risk factors 3
• Postpartum follow-up at 6 weeks should include blood pressure check and assessment for persistent hypertension 3

Common Pitfalls to Avoid

• Starting aspirin too late: Efficacy is substantially reduced if initiated after 16 weeks gestation 1, 5
• Inadequate preconception optimization: Missing opportunities to identify and treat underlying conditions before pregnancy 2
• Standard prenatal care frequency: This high-risk patient requires more intensive monitoring than routine care 2
• Assuming all preeclampsia is the same: Early-onset and late-onset disease have different pathophysiology and recurrence patterns 5, 4