What are the next steps for a patient with mild preeclampsia at 37 weeks with a non-reactive Non-Stress Test (NST)?

Management of Mild Preeclampsia at 37 Weeks with Non-Reactive NST

This patient should proceed to delivery, as preeclampsia at ≥37 weeks is an absolute indication for delivery regardless of NST results. 1, 2

Immediate Next Steps

1. Further Fetal Assessment

While delivery is indicated, you should perform additional fetal testing to determine the urgency and mode of delivery:

• Perform a biophysical profile (BPP) including ultrasound assessment of fetal biometry, amniotic fluid volume, fetal breathing movements, body movements, and tone 1, 2
• Continue electronic fetal monitoring to assess for decelerations or other concerning patterns that would indicate non-reassuring fetal status requiring expedited delivery 2, 3
• A non-reactive NST alone has limited predictive value and should not be used in isolation; multiple assessment modalities improve accuracy 4

2. Maternal Stabilization Prior to Delivery

Blood Pressure Management:

• Assess current blood pressure and treat if ≥140/90 mmHg with target diastolic BP of 85 mmHg and systolic BP 110-140 mmHg 1, 2
• Use oral nifedipine, labetalol, or methyldopa for non-severe hypertension 1
• If BP ≥160/110 mmHg, initiate urgent treatment with oral nifedipine or IV labetalol/hydralazine in a monitored setting 1, 2, 3

Seizure Prophylaxis:

• Administer magnesium sulfate if the patient has proteinuria with severe hypertension (≥160/110 mmHg) or any neurological signs/symptoms (headache, visual changes) 1, 2
• Loading dose: 4-5g IV over 5 minutes, followed by maintenance infusion of 1-2g/hour 3

3. Laboratory Assessment

Obtain the following labs to assess for progression to severe features:

• Complete blood count focusing on hemoglobin and platelet count 2, 3
• Comprehensive metabolic panel including liver transaminases (AST/ALT), creatinine, and uric acid 1, 2
• Urine protein/creatinine ratio if not already documented (≥30 mg/mmol or 0.3 mg/mg confirms significant proteinuria) 1

4. Clinical Monitoring

• Assess for symptoms of severe features: severe headache, visual scotomata, epigastric or right upper quadrant pain, shortness of breath 1, 3
• Physical examination including assessment for clonus and deep tendon reflexes 1
• Continuous vital signs including pulse oximetry 2, 3

Delivery Planning

Mode and Timing:

• Plan for delivery after maternal stabilization (if severe features present) 3
• Vaginal delivery is preferred unless cesarean is indicated for standard obstetric reasons 3
• The gestational age of 37 weeks meets the threshold for delivery in preeclampsia, eliminating the need for expectant management 1

Critical Pitfalls to Avoid

• Do not delay delivery based solely on the non-reactive NST; at 37 weeks with preeclampsia, delivery is indicated regardless of fetal testing results 1
• Do not underestimate disease severity based on the "mild" classification—all preeclampsia can rapidly progress to emergencies 1, 2
• Do not use uric acid level or degree of proteinuria as criteria for timing of delivery 1
• Do not perform plasma volume expansion routinely 1

Rationale

The International Society for the Study of Hypertension in Pregnancy (ISSHP) guidelines clearly state that women with preeclampsia should be delivered at 37 weeks and zero days gestation 1. This recommendation is based on the balance between maternal risk (which increases with expectant management) and fetal maturity (which is adequate at term). The non-reactive NST is concerning for potential fetal compromise but does not change the fundamental management, which is delivery at this gestational age 2. Additional testing helps determine urgency and mode of delivery but should not delay the decision to proceed with delivery 4.