What is the recommended management for hypertension in pregnancy?

Management of Hypertension in Pregnancy

For hypertension in pregnancy, the recommended management includes non-pharmacological approaches for mild cases and pharmacological treatment with methyldopa, labetalol, or nifedipine for moderate to severe cases, with treatment thresholds of ≥150/95 mmHg for most pregnant women and ≥140/90 mmHg for those with higher-risk conditions. 1

Classification of Hypertension in Pregnancy

• Hypertension in early pregnancy (before 20 weeks) is classified as pre-existing hypertension, affecting 1-5% of pregnancies 1
• Gestational hypertension is defined as hypertension developing after 20 weeks of gestation without proteinuria 1
• Pre-eclampsia is gestational hypertension with significant proteinuria (≥0.3 g/day in 24h collection or ≥30 mg/mmol urinary creatinine in spot sample) 2, 1
• Pre-existing hypertension with superimposed gestational hypertension occurs when pre-existing hypertension worsens with protein excretion ≥3 g/day after 20 weeks gestation 2, 1

Treatment Thresholds and Targets

• For women with gestational hypertension, pre-existing hypertension with superimposed gestational hypertension, or hypertension with subclinical organ damage, treatment should be initiated at BP ≥140/90 mmHg 2, 1
• For all other pregnant women with hypertension, treatment should be initiated at BP ≥150/95 mmHg 1, 3
• Target BP should be below 140/90 mmHg but not below 80 mmHg for diastolic BP to ensure adequate uteroplacental perfusion 1
• Severe hypertension (SBP ≥170 mmHg or DBP ≥110 mmHg) requires immediate hospitalization and treatment 2, 1

Non-Pharmacological Management

• Non-pharmacological management is recommended for pregnant women with SBP of 140-150 mmHg or DBP of 90-99 mmHg 2, 1
• A normal diet without salt restriction is advised, particularly close to delivery, as salt restriction may induce low intravascular volume 2, 1
• Limitation of activities and some bed rest in the left lateral position may be beneficial 2, 1
• Low-dose acetylsalicylic acid (75-100 mg/day) is recommended prophylactically in women with a history of early-onset (<28 weeks) pre-eclampsia, administered at bedtime starting before 16 weeks gestation 2, 1
• Calcium supplementation of at least 1g daily during pregnancy can reduce the risk of pre-eclampsia, especially in high-risk women 2

Pharmacological Management

• First-line medications for hypertension in pregnancy include: 1, 4

  • Methyldopa (longest safety record with adequate infant follow-up)
  • Labetalol
  • Dihydropyridine calcium channel blockers (preferably extended-release nifedipine)

• For severe hypertension (SBP ≥170 mmHg or DBP ≥110 mmHg), immediate treatment with IV labetalol, oral methyldopa, or nifedipine is recommended 2, 1

• Nifedipine may be preferred as first-line agent for severe hypertension as it has been associated with lower risk of persistent hypertension compared to hydralazine and labetalol 5

• ACE inhibitors, ARBs, and direct renin inhibitors are strictly contraindicated throughout pregnancy due to severe fetotoxicity 2, 1, 4

• Atenolol should be avoided due to concerns with fetal growth 6

Special Considerations and Monitoring

• Regular BP monitoring throughout pregnancy is essential 1
• Monitor for signs of worsening hypertension or development of pre-eclampsia (headache, visual disturbances, epigastric pain) 1
• Evaluate for proteinuria periodically to detect pre-eclampsia 1
• Methyldopa may interfere with laboratory tests including urinary catecholamines, which could complicate diagnosis of pheochromocytoma 7
• Labetalol may cause falsely elevated levels of urinary catecholamines and false-positive tests for amphetamine 8

Postpartum Management

• Continue antihypertensive medications postpartum with gradual tapering rather than abrupt cessation 1
• Safe antihypertensive medications for breastfeeding mothers include labetalol, nifedipine, methyldopa, and certain beta-blockers 1
• All women should be reviewed at 3 months postpartum to ensure BP, urinalysis, and laboratory abnormalities have normalized 1
• Women with a history of hypertensive disorders in pregnancy have increased long-term cardiovascular risks and require ongoing monitoring 1, 3

Hypertensive Emergencies in Pregnancy

• Hypertensive emergency in pregnancy is defined as pre-eclampsia/eclampsia with SBP ≥160 mmHg and DBP ≥110 mmHg or markedly elevated BP (DBP >120 mmHg) with progressive acute end-organ damage 2
• Risk factors for hypertensive emergencies include pre-eclampsia, cardiac disease, chronic renal disease, and non-compliance with antihypertensives 2
• For hypertensive emergencies, IV labetalol is now preferred over hydralazine 6
• Induction of delivery is indicated in gestational hypertension with proteinuria with adverse conditions such as visual disturbances, coagulation abnormalities, or fetal distress 1