What is the initial workup and management for a newly pregnant woman with hypertension?

Initial Workup and Management for a Newly Pregnant Woman with Hypertension

The initial workup for a newly pregnant woman with hypertension should include classification of hypertension type, comprehensive risk assessment, and prompt initiation of appropriate antihypertensive therapy, with labetalol or methyldopa as first-line medications.

Classification of Hypertension in Pregnancy

Proper classification is essential for appropriate management:

1. Chronic hypertension: Hypertension known before pregnancy or present in the first 20 weeks

   • Essential or secondary
   • White-coat hypertension
   • Masked hypertension

2. Gestational hypertension: New onset hypertension after 20 weeks without proteinuria

3. Preeclampsia: Hypertension after 20 weeks with proteinuria (≥0.3 g/day or ≥30 mg/mmol urinary creatinine)

4. Chronic hypertension with superimposed preeclampsia: Pre-existing hypertension with worsening BP and proteinuria after 20 weeks 1

Initial Diagnostic Workup

• Blood pressure measurement: Confirm hypertension (≥140/90 mmHg) with proper technique

• Urinalysis: Check for proteinuria (≥0.3 g/day in 24h collection or ≥30 mg/mmol creatinine in spot sample)

• Laboratory tests:

  • Complete blood count
  • Liver function tests
  • Renal function tests (creatinine, electrolytes)
  • Uric acid
  • Glucose

• Additional tests to consider based on clinical presentation:

  • 24-hour urine collection for protein if spot urine shows proteinuria
  • Ultrasound to assess fetal growth and placental function
  • Echocardiogram if cardiac disease is suspected 1

Management Approach

Non-Pharmacological Management

• Limited activity and rest in left lateral position (improves uteroplacental perfusion)
• Normal diet without salt restriction, especially close to delivery to avoid low intravascular volume 1
• Calcium supplementation (1.2-2.5 g/day) if intake likely to be low (<600 mg/day) 1
• Low-dose aspirin (75-100 mg/day) for women with risk factors for preeclampsia, starting before 16 weeks gestation 1
• Weight management: Avoid weight reduction during pregnancy, but limit excessive weight gain 1
• Regular exercise to maintain health and appropriate body weight 1

Pharmacological Management

For chronic hypertension in pregnancy:

• First-line medications:

  • Labetalol: Preferred due to established safety profile and low transfer to breast milk 2, 3
  • Methyldopa: Long-established safety record in pregnancy 4
  • Extended-release nifedipine: Alternative option 5

• Blood pressure targets:

  • Initiate treatment when BP ≥140/90 mmHg
  • Target BP <140/90 mmHg
  • Do not lower diastolic BP below 80 mmHg to maintain uteroplacental perfusion 1

• Medications to avoid:

  • ACE inhibitors
  • Angiotensin receptor blockers (ARBs)
  • Direct renin inhibitors
  • Atenolol (associated with fetal growth restriction) 1, 2

Emergency Management

• BP ≥170/110 mmHg: Requires immediate hospitalization
• Treatment options for severe hypertension:
  • IV labetalol
  • Oral methyldopa
  • Oral nifedipine
  • Avoid IV hydralazine due to increased perinatal adverse effects 1

Monitoring and Follow-up

• Regular BP monitoring: At least weekly in stable patients
• Fetal assessment: Regular ultrasound to monitor fetal growth
• Laboratory tests: Repeat periodically to monitor for preeclampsia
• Postpartum monitoring: Continue BP monitoring for at least 3 days in hospital and 7-10 days after discharge 1, 2

Recent Evidence and Special Considerations

The CHAP trial demonstrated that treating mild chronic hypertension in pregnancy to a goal of <140/90 mmHg (primarily with labetalol or nifedipine) reduced the risk of adverse outcomes including superimposed preeclampsia, preterm birth, placental abruption, and fetal/neonatal death 6.

Long-term Considerations

• Postpartum follow-up: All women should be reviewed at 3 months postpartum to ensure BP and laboratory abnormalities have normalized
• Long-term cardiovascular risk: Women with hypertensive disorders in pregnancy have increased lifetime risk of cardiovascular disease
• Annual medical review is recommended lifelong
• Lifestyle modifications: Exercise, healthy diet, and weight management 1

Common Pitfalls to Avoid

• Abrupt cessation of antihypertensive medications: Taper slowly to avoid rebound hypertension
• NSAIDs for postpartum analgesia: Avoid in women with preeclampsia, especially with renal disease or risk factors for acute kidney injury
• Inadequate postpartum monitoring: Eclamptic seizures can develop for the first time in the early postpartum period 1
• Overlooking long-term cardiovascular risk: Ensure proper follow-up and preventive strategies