What is the recommended management for a pregnant woman with hypertension, according to the Royal College of Obstetricians and Gynaecologists (RCOG) guideline?

Management of Hypertension in Pregnancy According to RCOG-Aligned Guidelines

Blood Pressure Treatment Thresholds

Initiate antihypertensive therapy at BP ≥140/90 mmHg in pregnant women with gestational hypertension, pre-existing hypertension with superimposed gestational hypertension, or hypertension with subclinical organ damage or symptoms. 1, 2

• For chronic hypertension without these specific features, treatment begins at BP ≥150/95 mmHg 1, 2
• Target diastolic BP of 85 mmHg and systolic BP of 110-140 mmHg during treatment 3, 1, 2
• This approach reduces the likelihood of developing severe maternal hypertension and complications such as low platelets and elevated liver enzymes 3
• Reduce or cease antihypertensive drugs if diastolic BP falls below 80 mmHg 3

The evidence supporting these thresholds comes from the CHIPS trial, which demonstrated that targeting a diastolic BP of 85 mmHg reduced accelerated maternal hypertension without adverse fetal outcomes 3.

Urgent Management of Severe Hypertension

BP ≥160/110 mmHg constitutes a hypertensive emergency requiring immediate treatment within 15 minutes in a monitored setting to prevent maternal stroke. 1, 2

First-line agents for acute severe hypertension include:

• Oral immediate-release nifedipine 1, 2
• Intravenous labetalol 3, 1, 2
• Intravenous hydralazine 3, 1

The goal is to reduce BP by at least 25% initially, then gradually to below 140/105 mmHg, but not lower than 130/90 mmHg to avoid compromising uteroplacental perfusion 4.

First-Line Antihypertensive Medications for Chronic Control

The three preferred agents for ongoing BP control during pregnancy are methyldopa, labetalol, and long-acting nifedipine. 1, 2

• Methyldopa is considered the drug of choice based on 7.5 years of infant follow-up safety data, but should be avoided postpartum due to risk of postnatal depression 2
• Labetalol has efficacy comparable to methyldopa and can be given intravenously for severe hypertension 2
• Long-acting nifedipine is effective for both chronic control and acute management 2
• Metoprolol is recommended as an alternative beta-blocker 1, 2

Critical precaution: Do not administer labetalol concomitantly with calcium channel blockers due to risk of severe hypotension. 2

Absolutely Contraindicated Medications

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

Indications for Immediate Hospitalization

Admit immediately for:

• BP ≥160/110 mmHg 1, 2
• Development of preeclampsia features (proteinuria with hypertension) 1, 2
• Neurological signs or symptoms (visual disturbances, severe headache) 1, 2
• Inability to control BP with ≥3 antihypertensive drug classes 1, 2

Monitoring for Gestational Hypertension

Monitor for developing preeclampsia using urinalysis at each visit along with clinical assessment and blood tests (hemoglobin, platelet count, liver transaminases, uric acid, and creatinine) at 28 and 34 weeks as a minimum. 3

• Assess fetal well-being with ultrasound from 26 weeks' gestation, then at 2-4 weekly intervals if fetal biometry is normal 3, 2
• More frequent monitoring is required in the presence of suspected fetal growth restriction 3
• Monitor fetal growth especially if maternal uric acid is elevated 3
• At least 25% of women with gestational hypertension will progress to preeclampsia, with highest risk among those presenting before 34 weeks 3

Preeclampsia-Specific Management

Administer magnesium sulfate for seizure prophylaxis in women with preeclampsia who have proteinuria and severe hypertension, or hypertension with neurological signs or symptoms. 1, 2

• In low-resource settings, all women with preeclampsia should receive MgSO4: loading dose of 4 g IV or 10 g IM, followed by 5 g IM every 4 hours or 1 g/h infusion until delivery and for at least 24 hours postpartum 3
• Critical precaution: Do not administer magnesium sulfate concomitantly with calcium channel blockers due to risk of severe hypotension 5, 2
• Administer prenatal corticosteroids for fetal lung maturation between 24+0 and 34+0 weeks if delivery is likely within 7 days 2

Timing of Delivery

For gestational hypertension without preeclampsia features, delivery can be delayed until 39+6 weeks provided BP can be controlled, fetal monitoring is reassuring, and preeclampsia has not developed. 3, 2

• Indications for earlier delivery are similar to those of preeclampsia 3
• For preeclampsia at term, recommend delivery 2
• Delivery may not immediately reduce BP; ongoing oral therapy (methyldopa, labetalol) is often needed after initial treatment with rapid-acting agents 3

Prevention Strategies

Low-dose aspirin (75-100 mg/day) should be administered at bedtime in women with a history of early-onset preeclampsia, starting pre-pregnancy or from diagnosis of pregnancy but before 16 weeks gestation, and continued until delivery. 1, 2

• Calcium supplementation of at least 1 g daily during pregnancy almost halved the risk of preeclampsia, with greatest effect in high-risk women 1, 2

Postpartum Management

Switch from methyldopa to alternative agent postpartum due to postnatal depression risk. 2

• BP typically rises over the first 5 postpartum days; women may become hypertensive again after initial normalization 2
• Consider breastfeeding compatibility when selecting antihypertensive therapy 4

Long-Term Cardiovascular Risk

Women with gestational hypertension or preeclampsia have significantly increased lifetime cardiovascular risk, with relative risk of ischemic heart disease more than doubled. 1, 2

• Recommend annual medical review lifelong for cardiovascular risk assessment, lifestyle modifications, regular blood pressure control, and control of metabolic factors 1, 2
• Women with early-onset preeclampsia, stillbirth, or fetal growth retardation are at highest risk 2
• Earlier onset in the first pregnancy correlates with greater recurrence risk in subsequent pregnancies 2