Antihypertensive Medications for Pregnant Women
Labetalol, extended-release nifedipine, and methyldopa are the recommended first-line antihypertensive medications for pregnant women with hypertension, while ACE inhibitors, ARBs, and direct renin inhibitors are absolutely contraindicated due to severe fetotoxicity. 1, 2, 3
First-Line Antihypertensive Agents
For Non-Severe Hypertension (140-159/90-109 mmHg)
Labetalol is a first-line beta-blocker with efficacy comparable to methyldopa, used in 74.9% of treated pregnant patients in real-world practice 3, 4. It can be administered orally for non-severe hypertension or intravenously for severe cases 3. The main contraindication is reactive airway disease (asthma) 2.
Extended-release nifedipine is the preferred calcium channel blocker during pregnancy, with established safety data and the advantage of once-daily dosing to improve adherence 2, 3. It is used in 29.6% of treated pregnant patients 4. The long-acting formulation should be used for maintenance therapy, while short-acting nifedipine is reserved only for rapid treatment of severe hypertension 2, 3.
Methyldopa has the longest safety record with long-term infant follow-up data 2, 3. However, it should be used with caution in women at risk of depression and must be switched to an alternative agent postpartum due to increased risk of postpartum depression 1, 5, 3.
For Severe Hypertension (≥160/110 mmHg)
Severe hypertension (systolic BP ≥170 mmHg or diastolic BP ≥110 mmHg) constitutes a medical emergency requiring hospitalization and treatment within 30-60 minutes 1, 5, 3.
IV labetalol is recommended as first-line treatment for acute severe hypertension, starting with 20 mg IV bolus, followed by 40-80 mg every 10 minutes until desired effect or maximum cumulative dose of 300 mg 1, 5.
Oral immediate-release nifedipine (10-20 mg) is an alternative first-line option for acute severe hypertension 1, 5.
IV hydralazine (5 mg initially, then 5-10 mg every 30 minutes) can be used as an alternative, though it is no longer the drug of choice due to association with more perinatal adverse effects than other agents 1, 5.
Blood Pressure Targets During Pregnancy
Target blood pressure should be 110-135/85 mmHg to reduce the risk of accelerated maternal hypertension while minimizing impairment of fetal growth 2, 3. Treatment should be initiated for confirmed systolic BP ≥140 mmHg or diastolic BP ≥90 mmHg in women with gestational hypertension (with or without proteinuria), pre-existing hypertension with superimposed gestational hypertension, or hypertension with subclinical organ damage 1, 3. In other circumstances, treatment thresholds are systolic BP ≥150 mmHg or diastolic BP ≥95 mmHg 1.
Medications to Absolutely Avoid
ACE inhibitors, angiotensin II receptor blockers (ARBs), and direct renin inhibitors are strictly contraindicated during pregnancy due to severe fetotoxicity, including fetal teratogenicity and oligohydramnios 1, 2, 3. These must be discontinued prior to conception or immediately upon pregnancy confirmation 2.
Atenolol should be avoided, especially in early pregnancy, due to concerns about fetal growth restriction 1, 5, 3.
Diuretics are generally not recommended as first-line agents due to risk of reducing uteroplacental perfusion, though they are not absolutely contraindicated 1, 2, 3.
Postpartum Management
Blood pressure may worsen after delivery, particularly between days 3-6 postpartum, which is when the majority of hypertension-related maternal deaths occur 1, 5, 3. Close BP monitoring is essential for at least 3 days postpartum 5.
Methyldopa must be switched to an alternative agent postpartum due to increased risk of postpartum depression 1, 5, 3. Preferred postpartum agents include nifedipine extended-release, amlodipine, enalapril, or labetalol, all of which are compatible with breastfeeding 5.
Avoid NSAIDs for postpartum analgesia in women with preeclampsia, especially those with renal disease, as NSAIDs can worsen hypertension 5.
Additional Management Considerations
Low to moderate-intensity exercise is recommended for all pregnant women without contraindications to reduce the risk of gestational hypertension and pre-eclampsia 3. Normal diet without salt restriction is advised, particularly close to delivery, as salt restriction may induce low intravascular volume 3.
Calcium supplementation of at least 1g daily during pregnancy may help reduce the risk of pre-eclampsia 1, 3.
Women with hypertension during pregnancy have significantly increased risk of developing chronic hypertension, stroke, ischemic heart disease, and thromboembolic disease later in life, requiring cardiovascular risk assessment and lifestyle modifications 2, 5, 3.
Common Pitfalls to Avoid
- Do not continue ACE inhibitors or ARBs during pregnancy even if well-controlled on these agents pre-pregnancy; switch to safe alternatives before conception 2, 3
- Do not use methyldopa postpartum due to depression risk; transition to alternative agents 1, 5
- Do not discharge patients with preeclampsia without a clear BP monitoring plan for the critical first 3-7 days when BP peaks 5
- Do not use short-acting nifedipine for maintenance therapy; reserve it only for acute severe hypertension 2, 3
- Do not prescribe NSAIDs liberally for postpartum pain in women with hypertensive disorders, especially with renal involvement 5