What is the best management approach for a pregnant patient with hypertension?

Management of Hypertension in Pregnancy

Initiate antihypertensive treatment when blood pressure reaches ≥140/90 mmHg in pregnant women with chronic or gestational hypertension, targeting BP <140/90 mmHg but not below 80 mmHg diastolic, using methyldopa, labetalol, or extended-release nifedipine as first-line agents. 1, 2

Blood Pressure Thresholds for Treatment Initiation

• Start pharmacological treatment at confirmed office BP ≥140/90 mmHg (or home BP ≥135/85 mmHg) in both chronic hypertension and gestational hypertension. 1, 2, 3
• This threshold applies equally to women with gestational hypertension (new onset after 20 weeks) and those with pre-existing chronic hypertension. 1, 2
• The 2024 ESC guidelines represent the most current evidence, superseding older recommendations that suggested higher thresholds of 150/95 mmHg. 1

Target Blood Pressure Range

• Target systolic BP to 110-140 mmHg and diastolic BP to 85 mmHg, but never allow diastolic BP to fall below 80 mmHg. 1, 2
• This range balances maternal cardiovascular protection against the risk of compromising uteroplacental perfusion. 1, 3
• The CHIPS trial demonstrated that targeting diastolic BP of 85 mmHg reduced accelerated maternal hypertension without adverse fetal outcomes. 1

First-Line Antihypertensive Medications

Three medications are recommended as first-line agents: 1, 2, 3

• Extended-release nifedipine (dihydropyridine calcium channel blocker): Preferred for once-daily dosing and strong safety profile. 1, 2, 3
• Labetalol (combined alpha/beta-blocker): Excellent alternative, particularly effective for women without reactive airway disease. 1, 2, 3
• Methyldopa (centrally-acting alpha-agonist): Has the longest safety record with 7.5-year infant follow-up data, though should be avoided in women at risk for depression. 2, 3, 4

Medication-Specific Considerations

• Methyldopa must be switched postpartum due to risk of postnatal depression. 3, 4
• Labetalol should not be used concomitantly with calcium channel blockers due to risk of severe hypotension. 3, 5
• Avoid atenolol as it is associated with intrauterine growth restriction. 6, 7
• Diuretics should generally be avoided during pregnancy due to risk of reducing uteroplacental perfusion, though they may be continued if already established before pregnancy. 6

Absolutely Contraindicated Medications

ACE inhibitors, angiotensin receptor blockers (ARBs), direct renin inhibitors, and mineralocorticoid receptor antagonists are strictly contraindicated throughout pregnancy due to associations with fetal teratogenicity, oligohydramnios, and fetopathy. 1, 2, 3, 6, 7

Management of Severe Hypertension (Hypertensive Emergency)

BP ≥160/110 mmHg constitutes a hypertensive emergency requiring immediate treatment within 15 minutes in a monitored setting to prevent maternal stroke. 1, 2, 3

Acute Management Options:

• Oral immediate-release nifedipine: First-line option for acute management. 1, 2, 3
• Intravenous labetalol: Equally effective alternative. 1, 2, 3
• Intravenous hydralazine: Third option for acute management. 1, 2

Classification and Monitoring Strategy

Chronic Hypertension

• Defined as hypertension present before pregnancy or diagnosed before 20 weeks gestation. 2, 3
• Requires baseline laboratory assessment including complete blood count, liver enzymes, serum creatinine, electrolytes, uric acid, and urinalysis with protein-to-creatinine ratio. 2
• Key risks include superimposed preeclampsia (25% risk), fetal growth restriction, and accelerated maternal hypertension. 1, 8

Gestational Hypertension

• Defined as new-onset hypertension at or after 20 weeks without proteinuria. 2, 3
• Approximately 25% will progress to preeclampsia, with highest risk among those presenting before 34 weeks. 1, 2
• Monitor for preeclampsia development using urinalysis at each visit plus blood tests (hemoglobin, platelet count, liver transaminases, uric acid, creatinine) at minimum at 28 and 34 weeks. 1

Fetal Monitoring Requirements

• Assess fetal growth with ultrasound starting at 26 weeks gestation, then every 2-4 weeks if biometry is normal. 1, 3
• More frequent monitoring is required if fetal growth restriction is suspected or if maternal uric acid is elevated. 1
• For absent end-diastolic flow in umbilical artery before 34 weeks, perform daily cardiotocograph monitoring, twice-weekly umbilical artery Doppler, and amniotic fluid volume assessment. 3

Indications for Hospitalization

Admit immediately for: 2, 3

• BP ≥160/110 mmHg (severe hypertension)
• Development of preeclampsia features
• Neurological signs or symptoms (visual disturbances, severe headache)
• Inability to control BP with ≥3 antihypertensive drug classes

Timing of Delivery

Gestational Hypertension Without Preeclampsia

• Delivery can be delayed until 39+6 weeks provided BP remains controlled, fetal monitoring is reassuring, and preeclampsia has not developed. 1, 2, 3

Preeclampsia

• Delivery at term (≥37 weeks) is recommended for preeclampsia. 2
• Earlier delivery is indicated with adverse conditions such as visual disturbances, coagulation abnormalities, or fetal distress. 3

Preeclampsia-Specific Management

• Magnesium sulfate should be administered for seizure prophylaxis in preeclampsia and for treatment of eclampsia. 2, 3
• In low-resource settings, use loading dose of 4 g IV or 10 g IM, followed by 5 g IM every 4 hours or infusion of 1 g/h until delivery and for at least 24 hours postpartum. 1
• Do not administer magnesium sulfate with calcium channel blockers due to severe hypotension risk. 3, 9
• Administer antenatal corticosteroids between 24+0 and 34+0 weeks if delivery is likely within 7 days for fetal lung maturation. 2, 3

Prevention Strategies

Low-Dose Aspirin

• Start low-dose aspirin (75-150 mg/day) at bedtime in women with history of early-onset preeclampsia, beginning pre-pregnancy or before 16 weeks gestation, continued until delivery. 3, 8, 10

Calcium Supplementation

• Calcium supplementation (≥1 g daily) almost halves preeclampsia risk, with greatest effect in high-risk women. 3

Exercise

• Low- to moderate-intensity exercise is recommended in consultation with an obstetrician for all pregnant women without contraindications to reduce risk of gestational hypertension and preeclampsia. 1, 2

Postpartum Management

• Record BP shortly after birth and again within 6 hours, continuing antihypertensive treatment as needed to maintain BP <140/90 mmHg. 2
• Switch from methyldopa to alternative agent postpartum due to postnatal depression risk. 3, 4
• BP typically rises over first 5 postpartum days; women may become hypertensive again after initial normalization. 3
• Hypertensive disorders can worsen or initially present after delivery and account for up to 44% of pregnancy-related deaths in the first 6 days postpartum. 10

Long-Term Cardiovascular Risk

• Women with gestational hypertension or preeclampsia have significantly increased lifetime cardiovascular risk, with relative risk of ischemic heart disease more than doubled. 2, 3, 11, 10
• Recommend annual medical review lifelong for cardiovascular risk assessment. 2, 3
• Women with early-onset preeclampsia, stillbirth, or fetal growth retardation are at highest risk. 3
• Lifestyle modifications, regular blood pressure control, and control of metabolic factors are necessary to reduce future cardiovascular risk. 3

Common Pitfalls to Avoid

• Do not delay treatment waiting for BP to reach 150/95 mmHg or higher—the 2024 ESC guidelines clearly recommend treatment at ≥140/90 mmHg. 1
• Do not use short-acting nifedipine for maintenance therapy—only extended-release formulations should be used for chronic management, with immediate-release reserved for hypertensive emergencies. 2, 3
• Do not continue ACE inhibitors or ARBs in women planning pregnancy—these must be discontinued before conception attempts begin. 1, 2, 3, 8
• Do not allow diastolic BP to fall below 80 mmHg, as this may compromise uteroplacental perfusion. 1
• Recognize that BP may appear normal in early pregnancy due to physiological fall, potentially masking pre-existing hypertension. 3
• Do not assume gestational hypertension is benign—at least 25% will progress to preeclampsia. 1