From the Guidelines
Labetalol, methyldopa, and nifedipine are the safest antihypertensive medications for use during pregnancy, as recommended by the most recent guidelines 1.
Key Considerations
- For mild to moderate hypertension, methyldopa (250-500 mg twice daily) is often the first-line choice due to its long safety record.
- Labetalol (100-400 mg twice daily) is an excellent alternative that works well for moderate to severe hypertension.
- For urgent blood pressure control, immediate-release nifedipine (10-20 mg) can be used.
Important Safety Information
- Avoid ACE inhibitors, ARBs, and direct renin inhibitors throughout pregnancy as they can cause fetal renal damage and other congenital abnormalities 1.
- Beta-blockers other than labetalol (like atenolol) should generally be avoided in the first trimester due to potential growth restriction concerns.
- Diuretics are typically not recommended as first-line agents but may be continued if the patient was on them before pregnancy.
Monitoring and Goals
- Blood pressure goals during pregnancy should be 140-150/90-100 mmHg to maintain adequate placental perfusion while preventing maternal complications.
- Regular monitoring of both maternal blood pressure and fetal growth is essential when using any antihypertensive medication during pregnancy 1.
Additional Recommendations
- Women with preeclampsia should be assessed in hospital when first diagnosed, and some may be managed as outpatients once it is established that their condition is stable 1.
- Fetal monitoring in preeclampsia should include an initial assessment to confirm fetal well-being, and maternal monitoring should include BP monitoring, repeated assessments for proteinuria, and clinical assessment including clonus 1.
From the FDA Drug Label
Pregnancy Teratogenic Effects. Reproduction studies performed with methyldopa at oral doses up to 1000 mg/kg in mice, 200 mg/kg in rabbits and 100 mg/kg in rats revealed no evidence of harm to the fetus. Published reports of the use of methyldopa during all trimesters indicate that if this drug is used during pregnancy the possibility of fetal harm appears remote. In five studies, three of which were controlled, involving 332 pregnant hypertensive women, treatment with methyldopa was associated with an improved fetal outcome
Methyldopa is considered safe for use during pregnancy. The drug label states that reproduction studies in animals showed no evidence of harm to the fetus, and published reports indicate that the possibility of fetal harm appears remote. Additionally, studies involving pregnant hypertensive women showed an improved fetal outcome with methyldopa treatment 2.
Labetalol and prazosin are categorized as Pregnancy Category C, meaning that they should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus 3 4.
- Key points:
- Methyldopa: safe for use in pregnancy
- Labetalol and prazosin: use during pregnancy only if potential benefit justifies potential risk
- Main consideration: the decision to use any of these medications during pregnancy should be made with caution and under the guidance of a healthcare provider.
From the Research
Antihypertensive Medications Safe for Pregnancy
- Methyldopa, labetalol, and calcium antagonists (such as nifedipine) are considered safe for use during pregnancy 5, 6, 7, 8, 9
- These medications are recommended by European guidelines for initiating drug treatment in pregnant women with persistent elevation of blood pressure ≥ 150/95 mmHg and at values > 140/90 mmHg in women with gestational hypertension 5
- Labetalol is the most frequently used medication, followed by nifedipine and hydralazine, according to a retrospective, observational cohort study 6
- A randomized controlled trial found that nifedipine retard, labetalol, and methyldopa are viable initial options for treating severe hypertension in low-resource settings 7
- Pharmacokinetic studies have found no fetal accumulation of methyldopa, labetalol, and nifedipine, but more research is needed to determine the optimal dosing and blood pressure targeting during pregnancy 8
Recommendations for Antihypertensive Medication Use in Pregnancy
- Oral α-methyldopa and parenteral labetalol are recommended as the drugs of choice for nonsevere and severe hypertension in pregnancy, respectively 9
- Long-acting nifedipine is recommended as an alternative for first-line and second-line therapy in nonsevere and severe hypertension 9
- The use of β-blockers, such as atenolol, is contraindicated in early and late stages of pregnancy according to several guidelines 9
- Diuretic-associated harmful effects on maternal and fetal outcomes are controversial, and their use is discouraged in pregnancy 9