Treatment of Hypertension in Pregnancy
For hypertension in pregnancy, first-line treatment includes oral methyldopa, labetalol, or nifedipine, with the goal of maintaining blood pressure between 110-140/85 mmHg to reduce maternal complications while avoiding fetal compromise. 1, 2
Classification of Hypertension in Pregnancy
- Hypertension in pregnancy is classified as: chronic hypertension (present before 20 weeks), gestational hypertension (arising after 20 weeks without proteinuria), or preeclampsia (hypertension with proteinuria after 20 weeks) 1
- Severe hypertension is defined as blood pressure >160/110 mmHg and requires urgent treatment 1
Treatment of Severe Hypertension (>160/110 mmHg)
- Severe hypertension requires urgent treatment in a monitored setting to prevent maternal complications such as stroke 1
- First-line medications for severe hypertension include:
- Oral nifedipine: 10 mg, which can be repeated every 20 minutes to a maximum of 30 mg 3
- IV labetalol: initial 20 mg bolus, then 40 mg if needed after 10 minutes, followed by 80 mg every 10 minutes to a maximum of 220 mg 3
- IV hydralazine: 5 mg bolus, then 10 mg every 20-30 minutes to a maximum of 25 mg 3
- Oral labetalol may be used if IV medications are unavailable 1
- Recent evidence suggests nifedipine may be superior to hydralazine for successful treatment of severe hypertension (OR 4.13 [95% CrI 1.01-20.75]) 4
Treatment of Non-Severe Hypertension (140-159/90-109 mmHg)
- Blood pressure consistently at or above 140/90 mmHg should be treated, aiming for a target diastolic BP of 85 mmHg (and systolic BP of 110-140 mmHg) 1
- First-line oral medications include:
- Second or third-line agents include hydralazine and prazosin 1
- Antihypertensive drugs should be reduced or ceased if diastolic BP falls below 80 mmHg 1
Medications to Avoid in Pregnancy
- ACE inhibitors, angiotensin II receptor blockers (ARBs), direct renin inhibitors, and mineralocorticoid receptor antagonists are contraindicated throughout pregnancy due to fetotoxicity 2, 6
- Diuretics should generally be avoided as they may reduce uteroplacental perfusion 2
- Beta-blockers, particularly atenolol, should be used with caution, especially in early pregnancy 2, 6
Management Based on Hypertension Type
Chronic Hypertension
- Continue antihypertensive medication but switch from contraindicated medications (ACE inhibitors, ARBs) to pregnancy-safe alternatives before conception or as soon as pregnancy is confirmed 2
- Regular monitoring of maternal and fetal well-being is essential 1
Gestational Hypertension and Preeclampsia
- More intensive monitoring is required, including assessment for proteinuria and other signs of preeclampsia 1
- Women with preeclampsia who have severe hypertension or neurological symptoms should receive magnesium sulfate for seizure prophylaxis 1
- Consider delivery at 37 weeks or earlier if there are complications such as severe uncontrolled hypertension, progressive organ dysfunction, or fetal compromise 1
Postpartum Management
- Blood pressure should be monitored closely after delivery, with recordings shortly after birth and again within 6 hours 1
- Antihypertensive medications may need to be continued postpartum and should be withdrawn slowly over days 1
- NSAIDs for postpartum analgesia should be avoided in women with preeclampsia 1
- All women should be reviewed at 3 months postpartum to ensure BP and any laboratory abnormalities have normalized 1
Recent Evidence on Comparative Efficacy
- A 2019 randomized controlled trial comparing oral nifedipine, labetalol, and methyldopa for severe hypertension found that nifedipine resulted in better blood pressure control (84%) compared to methyldopa (76%) 7
- A network meta-analysis confirmed that nifedipine was superior to hydralazine for successful treatment of severe hypertension without increased risk for cesarean delivery or maternal side effects 4