What is the recommended management for hypertension in pregnancy?

Management of Hypertension in Pregnancy

The recommended management for hypertension in pregnancy includes prompt initiation of antihypertensive medication for blood pressure ≥140/90 mmHg, with first-line agents being methyldopa, labetalol, or dihydropyridine calcium channel blockers (preferably nifedipine), along with close monitoring and lifestyle modifications. 1

Classification of Hypertensive Disorders in Pregnancy

Hypertension in pregnancy is classified into several categories:

1. Pre-existing hypertension (chronic hypertension)

   • Present before pregnancy or diagnosed before 20 weeks gestation
   • May include essential or secondary hypertension

2. Gestational hypertension

   • New onset hypertension after 20 weeks gestation without proteinuria
   • Usually resolves within 42 days postpartum

3. Preeclampsia

   • Gestational hypertension with proteinuria (≥0.3 g/day or ≥30 mg/mmol urinary creatinine)
   • Can occur de novo or superimposed on chronic hypertension

4. Pre-existing hypertension with superimposed gestational hypertension and proteinuria

   • Worsening of pre-existing hypertension with new proteinuria after 20 weeks 1

Diagnostic Criteria

• Hypertension in pregnancy is defined as systolic BP ≥140 mmHg and/or diastolic BP ≥90 mmHg
• Severe hypertension: systolic BP ≥160 mmHg or diastolic BP ≥110 mmHg
• Measurements should be taken at least twice, preferably 4 hours apart 1

Management Approach

Non-pharmacological Management

For mild hypertension (140-149/90-99 mmHg):

• Close supervision and limitation of activities
• Some bed rest in left lateral position
• Normal diet without salt restriction (salt restriction may reduce intravascular volume)
• Regular monitoring of maternal and fetal condition 1

Pharmacological Management

When to start medication:

• Current guidelines recommend initiating antihypertensive treatment when BP is ≥140/90 mmHg in:
  • Women with gestational hypertension (with or without proteinuria)
  • Women with pre-existing hypertension plus superimposed gestational hypertension
  • Women with hypertension and subclinical organ damage 1, 2

First-line medications:

1. Methyldopa

   • Drug of choice with the longest safety record in pregnancy
   • Has shown safety in long-term infant follow-up studies 1, 3

2. Labetalol

   • Alpha/beta-blocker with efficacy comparable to methyldopa
   • Can be given intravenously in severe hypertension 1, 4

3. Dihydropyridine calcium channel blockers

   • Preferably extended-release nifedipine
   • Effective and safe alternative 1, 5

Medications to avoid:

• ACE inhibitors and ARBs are strictly contraindicated due to fetotoxicity
• Atenolol should be used with caution due to association with fetal growth restriction
• Diuretics are generally not recommended 1

Management of Severe Hypertension (Emergency)

• Systolic BP ≥170 mmHg or diastolic BP ≥110 mmHg requires immediate hospitalization
• Treatment options:
  • Intravenous labetalol
  • Oral methyldopa
  • Oral nifedipine
  • For preeclampsia with pulmonary edema, nitroglycerin is preferred
  • Intravenous hydralazine should be avoided due to associated perinatal adverse effects 1

Prevention Strategies

1. Low-dose aspirin (75-100 mg/day)

   • Recommended for women at high risk of preeclampsia
   • Should be started before 16 weeks gestation and continued until delivery
   • Particularly beneficial for women with history of early-onset preeclampsia (<28 weeks) 1

2. Calcium supplementation (1.2-2.5 g/day)

   • Recommended for women with low calcium intake (<600 mg/day)
   • May reduce risk of preeclampsia, particularly in high-risk women 1

3. Exercise

   • Low to moderate intensity exercise is recommended to reduce risk of gestational hypertension and preeclampsia 1

Postpartum Care

1. Early postpartum period

   • Women with preeclampsia should be considered high risk for at least 3 days
   • BP and clinical condition should be monitored at least every 4 hours while awake
   • Antihypertensive medications should be continued 1

2. Medication management

   • Consider treating any hypertension before day 6 postpartum
   • Antihypertensive therapy should be withdrawn slowly, not abruptly 1

3. Follow-up

   • All women should be reviewed at 3 months postpartum to ensure BP, urinalysis, and laboratory abnormalities have normalized
   • If proteinuria or hypertension persists, further investigation is needed 1

Long-term Considerations

• Women with history of hypertensive disorders in pregnancy have increased long-term cardiovascular risk
• Annual medical review is advised lifelong
• Healthy lifestyle including exercise, proper nutrition, and maintaining ideal body weight is recommended
• Aim to achieve pre-pregnancy weight by 12 months postpartum 1, 2

Common Pitfalls and Caveats

1. Failure to recognize severe hypertension as an emergency requiring immediate hospitalization
2. Inappropriate use of contraindicated medications (ACE inhibitors, ARBs)
3. Overly aggressive BP lowering, which may compromise uteroplacental perfusion
4. NSAIDs for postpartum analgesia should be avoided in women with preeclampsia
5. Neglecting long-term follow-up for women with history of hypertensive disorders in pregnancy 1

By following these evidence-based recommendations, healthcare providers can effectively manage hypertension in pregnancy to optimize maternal and fetal outcomes while minimizing complications.