What is the recommended treatment for hypertension in pregnancy?

Treatment of Hypertension in Pregnancy

For hypertension in pregnancy, initiate pharmacological treatment with methyldopa, labetalol, or extended-release nifedipine when blood pressure is persistently ≥140/90 mmHg, targeting BP <140/90 mmHg but keeping diastolic BP ≥80 mmHg. 1, 2

Blood Pressure Thresholds for Treatment

Initiate antihypertensive medication at BP ≥140/90 mmHg in the following situations: 1

• Gestational hypertension (with or without proteinuria)
• Pre-existing hypertension with superimposed gestational hypertension
• Any hypertension with organ dysfunction or symptoms
• Pre-eclampsia

For uncomplicated chronic hypertension without the above features, treatment should begin at BP persistently ≥150/95 mmHg. 1

Target blood pressure should be <140/90 mmHg, but avoid lowering diastolic BP below 80 mmHg to maintain adequate uteroplacental perfusion. 2

First-Line Pharmacological Options

The three recommended first-line medications are: 2, 3

Methyldopa:

• Has the longest safety record with documented long-term infant follow-up data (7.5 years) 1
• FDA labeling confirms no evidence of fetal harm in animal studies and improved fetal outcomes in clinical studies of 332 pregnant women 4
• Use with caution in women at risk for depression 3

Labetalol (alpha/beta-blocker):

• Efficacy comparable to methyldopa 1, 2
• Available in both oral and intravenous formulations for flexible dosing 2
• Contraindicated in women with reactive airway disease 3

Extended-release nifedipine (dihydropyridine calcium channel blocker):

• Strong safety profile with once-daily dosing that improves adherence 2, 3
• Use only long-acting formulation for maintenance; short-acting reserved for acute severe hypertension 3

Severe Hypertension/Hypertensive Emergency

Severe hypertension is defined as SBP ≥160 mmHg or DBP ≥110 mmHg and requires hospitalization with urgent treatment. 1, 2

Intravenous options for acute management: 2, 5

• IV labetalol (preferred)
• IV hydralazine
• Oral nifedipine (short-acting)

Sodium nitroprusside should only be used when all other treatments fail due to risk of fetal cyanide poisoning with prolonged use. 2

Strictly Contraindicated Medications

ACE inhibitors, angiotensin receptor blockers (ARBs), and direct renin inhibitors are absolutely contraindicated throughout pregnancy due to severe fetotoxicity, particularly in the second and third trimesters. 1, 2, 3

• If taken inadvertently in the first trimester, immediately switch to safe alternatives and arrange close fetal ultrasound monitoring 1
• Women on these medications who are planning pregnancy should be transitioned to safe alternatives before conception 3, 6

Atenolol should be avoided due to concerns with impaired fetal growth. 5

Non-Pharmacological Management and Prevention

Low-dose aspirin (75-100 mg daily) should be started before 16 weeks gestation in women with history of early-onset pre-eclampsia (<28 weeks). 1, 2

Calcium supplementation of at least 1 gram daily reduces pre-eclampsia risk, particularly in high-risk women. 1, 2

Low to moderate-intensity exercise is recommended for all pregnant women without contraindications to reduce risk of gestational hypertension and pre-eclampsia. 2

Dietary recommendations: 1

• Normal diet without salt restriction (salt restriction may induce low intravascular volume)
• Obese women should limit weight gain to <6.8 kg 1

Management of Pre-eclampsia

All pregnant women with hypertension should be screened for proteinuria in the second half of pregnancy. 1

Pre-eclampsia is diagnosed when gestational hypertension is accompanied by: 1

• Proteinuria (>0.3 g/24h or albumin-to-creatinine ratio ≥30 mg/mmol), OR
• Evidence of maternal organ dysfunction (renal, hepatic, neurological, hematological), OR
• Uteroplacental dysfunction (fetal growth restriction, abnormal Doppler)

Magnesium sulfate should be used for eclampsia and severe pre-eclampsia. 1

When pre-eclampsia is suspected, an sFlt-1/PlGF ratio ≤38 can exclude development of pre-eclampsia in the next week. 1

Postpartum Management

Antihypertensive medications should be withdrawn slowly over days, not ceased abruptly, as eclamptic seizures may develop in the early postpartum period. 1

NSAIDs for postpartum analgesia should be avoided in women with pre-eclampsia, especially if they have renal disease, placental abruption, or acute kidney injury. 1

All women should be reviewed at 3 months postpartum to ensure BP, urinalysis, and laboratory abnormalities have normalized. 1

Annual medical review is advised lifelong, as women with gestational hypertension or pre-eclampsia have significantly increased long-term cardiovascular risk. 1, 3

Critical Pitfalls to Avoid

• Never use ACE inhibitors, ARBs, or direct renin inhibitors during pregnancy 1, 2, 3
• Do not lower diastolic BP below 80 mmHg as this may impair uteroplacental perfusion 2
• Do not restrict salt intake during pregnancy, particularly near delivery 1
• Do not abruptly discontinue antihypertensives postpartum due to risk of rebound hypertension and eclampsia 1
• Do not use atenolol due to fetal growth concerns 5