Chronic Hypertension in Pregnancy

Initial Assessment and Diagnosis

The American College of Cardiology and Hypertension society recommend confirming chronic hypertension diagnosis, which is present before pregnancy or before 20 weeks gestation, to evaluate for end-organ damage and baseline labs 1

Medications that can cause significant teratogenic effects and fetal harm, such as inhibitors of the angiotensin-converting enzyme (ACE), angiotensin II receptor antagonists, direct renin inhibitors, and mineralocorticoid receptor antagonists, should be avoided during pregnancy, as stated by the American Heart Association, American College of Cardiology, and European Society of Cardiology 2, 3, 4, 5, 1, 6
First-line medications for treating hypertension during pregnancy include dihydropyridine calcium channel blockers (preferably nifedipine), labetalol, and methyldopa, as recommended by the European Society of Cardiology and American Heart Association 5, 2, 4
Atenolol should be avoided due to the risk of fetal growth restriction, according to the American College of Cardiology and American Heart Association 4, 2
Diuretics are not recommended for blood pressure control during pregnancy 7

Regular monitoring should include twice weekly blood tests for hemoglobin, platelet count, liver transaminases, creatinine, and uric acid, as well as ultrasound assessment of fetal biometry, amniotic fluid, and umbilical artery Doppler to monitor fetal well-being 1
Blood pressure should be monitored regularly, with urgent treatment required for BP ≥160/110 mmHg, as recommended by the Hypertension society 1
The European Society of Cardiology recommends maintaining blood pressure below 140/90 mmHg, with diastolic blood pressure not reduced below 80 mmHg 5
The American College of Cardiology recommends targeting a diastolic BP of 85 mmHg and systolic BP <160 mmHg, and reducing or ceasing antihypertensive drugs if diastolic BP falls <80 mmHg 1

Pharmacological treatment should be initiated when blood pressure is ≥140/90 mmHg in gestational hypertension or chronic hypertension during pregnancy, with recommended dosages:
Nifedipine should be used with caution when combined with magnesium sulfate due to the risk of precipitous BP drop, as stated by the American Heart Association 2
Labetalol should be used with caution in patients with reactive airway disease or asthma, and primary contraindications for labetalol include second or third-degree AV block, maternal systolic heart failure, and history of reactive airway disease/asthma 4, 8
Magnesium sulfate should be initiated for convulsion prophylaxis with a loading dose of 4g IV over 5 minutes followed by a maintenance dose of 1g/hour IV infusion, continuing for at least 24 hours postpartum 1, 5

Low to moderate intensity exercise is recommended in consultation with an obstetrician, along with close supervision and limitation of activities 5, 6
A normal diet without salt restriction is recommended, and weight reduction is not recommended during pregnancy, even in obese women 6
Non-pharmacological management, including close supervision, limitation of activities, and normal diet, may be considered for women with Stage 1 hypertension who are at low risk for cardiovascular complications during pregnancy, without pharmacological treatment 2

Pregnancy-induced hypertension (PIH) is classified as mild (SBP 140-149 and DBP 90-99 mmHg), moderate (SBP 150-159 and DBP 100-109 mmHg), or severe (SBP ≥160 and DBP ≥110 mmHg), as recommended by the European Society of Cardiology 6
Expectant management is appropriate at 31 weeks if maternal and fetal conditions remain stable, but delivery should be considered if any signs of worsening preeclampsia develop 1
Plan for delivery by 37 weeks if preeclampsia remains stable 8
Hospitalization should be considered if BP rises to ≥170/110 mmHg, which is considered an emergency 10
Hypertension can worsen after delivery, especially between days 3 and 6, and anti-hypertensive medications should be continued after delivery, with metildopa changed to an alternative in the postpartum period 11