Methyldopa Dosage in Pregnant Women with Hypertension
For pregnant women with hypertension, methyldopa should be initiated at 750 mg per day divided into three or four doses, with titration up to a maximum of 4 grams per day based on blood pressure response. 1
Initial Dosing Strategy
- Start with 750 mg daily in divided doses (typically 250 mg three times daily) for mild to moderate hypertension (BP 140-169/90-109 mmHg). 1
- The dose can be gradually increased weekly based on blood pressure response, with an average effective dose around 685 mg/day in clinical practice. 2
- Maximum daily dose is 4 grams per day, divided into three or four doses. 1
When to Initiate Treatment
- Begin methyldopa when BP reaches ≥140/90 mmHg in women with gestational hypertension, pre-existing hypertension with superimposed gestational hypertension, or hypertension with subclinical organ damage. 1
- In other circumstances without these risk factors, treatment threshold is ≥150/95 mmHg. 1
- Treatment should ideally begin before conception in women with known chronic hypertension. 1
Dose Titration and Monitoring
- As pregnancy advances, increasing doses are typically required to maintain blood pressure control. 3
- Weekly dose adjustments of 250 mg increments are appropriate based on blood pressure response. 2
- Target blood pressure is 140-150/90-100 mmHg to balance maternal protection while avoiding uteroplacental hypoperfusion. 4
Clinical Advantages and Safety Profile
- Methyldopa remains the first-line agent for chronic hypertension in pregnancy due to its extensive safety record with no evidence of adverse effects on mothers or babies, including long-term pediatric follow-up. 1
- The drug effectively prevents progression to severe hypertension and reduces the frequency of severe hypertension during labor. 3
- Treatment with methyldopa (versus no medication) significantly reduces maternal complications including severe hypertension, preeclampsia, renal impairment, placental abruption, and neonatal prematurity. 5
Important Caveats
- Discontinue methyldopa postpartum due to the risk of postnatal depression; alternative agents should be used after delivery. 1
- Approximately 14.5% of women may experience minor side effects including lack of energy, dizziness, drowsiness, headache, or postural hypotension, which may necessitate switching to alternative therapy. 3, 6
- Avoid overly aggressive blood pressure reduction (do not lower diastolic BP below 80 mmHg) as this can impair uteroplacental perfusion and compromise fetal development. 4
Severe Hypertension Management
- For hypertensive emergencies (BP ≥170/110 mmHg), hospitalization is mandatory and oral methyldopa can be used alongside or instead of IV labetalol or oral nifedipine for immediate treatment. 1
- In severe cases, a single dose of 1000 mg methyldopa has been studied, though standard escalating doses are more commonly used. 7