What is the treatment for a pregnant woman with hypertension?

Treatment of Hypertension in Pregnancy

For pregnant women with hypertension, initiate pharmacological treatment with methyldopa, labetalol, or extended-release nifedipine when blood pressure reaches ≥140/90 mmHg, targeting BP below 140/90 mmHg while maintaining diastolic BP above 80 mmHg to preserve uteroplacental perfusion. 1, 2, 3

Blood Pressure Thresholds and Treatment Goals

• Start antihypertensive medication when BP is persistently ≥140/90 mmHg in pregnant women with gestational hypertension, pre-existing hypertension with superimposed gestational hypertension, any hypertension with organ dysfunction or symptoms, or pre-eclampsia 1, 3

• For uncomplicated chronic hypertension without the above features, treatment should begin at BP persistently ≥150/95 mmHg 3

• Target BP should be below 140/90 mmHg but critically, diastolic BP must not fall below 80 mmHg to maintain adequate placental blood flow 1, 2, 3

• The American Diabetes Association supports targeting diastolic BP of 85 mmHg based on the CHIPS trial, which achieved mean systolic BP of 133 mmHg and diastolic of 85 mmHg, reducing maternal accelerated hypertension without adverse fetal outcomes 2

First-Line Pharmacological Options

Three medications are recommended as first-line therapy:

• Methyldopa has the longest safety record with documented long-term infant follow-up data extending to 7.5 years, making it the gold standard for pregnancy hypertension 3, 4

• Labetalol is an alpha/beta-blocker with efficacy comparable to methyldopa and is particularly useful when tachycardia coexists with hypertension, as it addresses both conditions simultaneously 1, 2, 3

• Extended-release nifedipine (a dihydropyridine calcium channel blocker) has a strong safety profile with once-daily dosing that improves adherence, though it may worsen tachycardia through reflex sympathetic activation 1, 2, 3

Medications That Are Absolutely Contraindicated

• ACE inhibitors, angiotensin receptor blockers (ARBs), and direct renin inhibitors are strictly contraindicated throughout pregnancy due to severe fetotoxicity, particularly in the second and third trimesters 5, 1, 2, 3

• Atenolol should be avoided as it is specifically contraindicated in pregnancy due to associations with intrauterine growth retardation 2

• Spironolactone is contraindicated as it may cause fetal damage 5

• Diuretics are not recommended for blood pressure control in pregnancy but may be used during late-stage pregnancy if needed for volume control 5

Management of Severe Hypertension (≥160/110 mmHg)

Severe hypertension requires immediate hospitalization and urgent treatment to prevent maternal stroke and eclampsia:

• Intravenous labetalol is the preferred option for acute management 3, 6

• Alternative intravenous options include hydralazine and nifedipine 1, 2

• Sodium nitroprusside should only be used when all other treatments fail due to risk of fetal cyanide poisoning with prolonged administration 1, 3

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) 2, 3

• Calcium supplementation of at least 1 gram daily reduces pre-eclampsia risk, particularly in high-risk women 1, 3

• Low to moderate-intensity exercise is recommended for all pregnant women without contraindications to reduce risk of gestational hypertension and pre-eclampsia 1, 3

• Sodium restriction to 2.4 g/day is recommended, though normal diet without severe salt restriction is advised near delivery to maintain intravascular volume 2

• Weight reduction should not be attempted, even in obese pregnant women, as it can lead to reduced neonatal weight 2

Critical Pitfalls to Avoid

• Do not aggressively lower diastolic BP below 80 mmHg—meta-analysis of 45 trials showed a direct linear relationship between treatment-induced fall in mean arterial pressure and proportion of small-for-gestational-age infants 2

• Do not continue ACE inhibitors or ARBs inadvertently discovered in early pregnancy—switch immediately to safe alternatives (methyldopa, labetalol, or nifedipine) and arrange close fetal ultrasound monitoring 2

• Do not use short-acting nifedipine, as it is not FDA-approved for hypertension management and can cause precipitous BP drops, especially with concurrent magnesium sulfate 2

• Do not delay delivery in severe preeclampsia regardless of gestational age if there are signs of fetal distress, intrauterine growth retardation, or maternal complications (HELLP syndrome, pulmonary edema, visual disturbances) 2

Postpartum Management

• Monitor BP for 72 hours in hospital and 7-10 days postpartum 5, 2

• Antihypertensive medications should be withdrawn slowly over days, not ceased abruptly, as eclamptic seizures may develop in the early postpartum period 3

• NSAIDs for postpartum analgesia should be avoided in women with pre-eclampsia, especially if they have renal disease, placental abruption, or acute kidney injury 3

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

• Annual cardiovascular risk assessment should be performed lifelong—women with gestational hypertension have 4-fold increased risk of future hypertension and 2-fold increased risk of ischemic heart disease 2, 3