Management of Pregnancy-Induced Hypertension
Initiate antihypertensive treatment when blood pressure reaches ≥140/90 mmHg in gestational hypertension, targeting diastolic BP of 85 mmHg and systolic BP of 110-140 mmHg, using methyldopa, labetalol, or long-acting nifedipine as first-line agents. 1, 2
Blood Pressure Thresholds and Treatment Initiation
Standard Treatment Threshold
- Start pharmacological treatment when office BP is ≥140/90 mmHg (or home BP ≥135/85 mmHg) in women with: 1, 2
- Gestational hypertension (new onset after 20 weeks)
- Pre-existing hypertension with superimposed gestational hypertension
- Hypertension with subclinical organ damage or symptoms at any time during pregnancy
Non-Pharmacological Management
- For BP 140-150/90-99 mmHg without the above features, non-pharmacological management is appropriate initially 3
- However, for women without these specific features but with chronic hypertension, treatment threshold is ≥150/95 mmHg 2
Severe Hypertension: Emergency Management
BP ≥160/110 mmHg constitutes a hypertensive emergency requiring immediate hospitalization and treatment within 15 minutes to prevent maternal stroke. 2, 4
Acute Treatment Options
- Oral immediate-release nifedipine is first-line for acute management 1, 2
- Intravenous labetalol is equally effective 1, 2, 4
- Intravenous hydralazine is an alternative option 1, 4
- Target BP reduction to systolic 140-150 mmHg and diastolic 90-100 mmHg 4
First-Line Antihypertensive Medications for Chronic Control
The three preferred agents are methyldopa, labetalol, and long-acting nifedipine. 1, 2, 5
Methyldopa
- Drug of choice in pregnancy with established safety profile 6, 7
- Critical caveat: Avoid postpartum due to risk of postnatal depression 3, 2
- May cause false-positive urine catecholamine levels, interfering with pheochromocytoma diagnosis 8
Labetalol
- Efficacy comparable to methyldopa 6, 7
- Critical caveat: Do not use concomitantly with calcium channel blockers due to risk of severe hypotension 2
- Small amounts (0.004% of maternal dose) excreted in breast milk 9
Long-Acting Nifedipine
- Safe and effective for chronic BP control 1, 5
- Immediate-release formulation used for acute severe hypertension 1, 2
Contraindicated Medications
- ACE inhibitors and angiotensin receptor blockers are absolutely contraindicated due to fetopathy risk 3, 6
Monitoring Strategy
Maternal Monitoring
- Regular clinical evaluation including assessment for clonus 5
- Urine analysis at each visit to detect proteinuria 5
- Laboratory tests (hemoglobin, platelets, liver enzymes, uric acid, creatinine) at minimum at 28 and 34 weeks 5
Fetal Monitoring
- Ultrasound evaluation of fetal well-being starting at 26 weeks 5
- Subsequent evaluations every 2-4 weeks if fetal biometry is normal 5
- More frequent monitoring if fetal growth restriction is suspected 5
Indications for Hospitalization
Admit immediately for any of the following: 1, 2, 5
- BP ≥160/110 mmHg (severe hypertension)
- Development of preeclampsia features
- Neurological signs or symptoms (visual disturbances, severe headache)
- Laboratory abnormalities suggesting disease progression
- Inability to control BP with ≥3 antihypertensive drug classes
Timing of Delivery
Gestational Hypertension Without Preeclampsia
- Delivery can be delayed until 39+6 weeks if BP remains controlled, fetal monitoring is reassuring, and preeclampsia has not developed 1, 5
- Optimal delivery timing appears to be 38-39 weeks based on retrospective data 5
Preeclampsia
- Delivery at term (≥37 weeks) is recommended 1
- Induction indicated with adverse conditions such as visual disturbances, coagulation abnormalities, or fetal distress 3
Preeclampsia-Specific Management
Seizure Prophylaxis
- Magnesium sulfate is recommended for seizure prophylaxis in preeclampsia and for treatment of eclampsia 1, 2, 7
- Critical caveat: Do not administer with calcium channel blockers due to severe hypotension risk 2
Corticosteroids
- Administer antenatal corticosteroids between 24+0 and 34+0 weeks if delivery is likely within 7 days 1
Postpartum Management
Blood Pressure Monitoring
- Record BP shortly after birth and again within 6 hours 1
- BP typically rises over first 5 postpartum days; women may become hypertensive again after initial normalization 2
- Continue antihypertensive treatment as needed to maintain BP <140/90 mmHg 1
Medication Adjustments
- Switch from methyldopa to alternative agent due to postnatal depression risk 3, 2
- Labetalol and nifedipine are safe alternatives postpartum 1
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 and risk of developing hypertension almost four-fold compared to women with normal pregnancies. 3, 2
Follow-Up Recommendations
- Annual medical review lifelong for cardiovascular risk assessment 1, 2
- Lifestyle modifications and regular BP control 3
- Control of metabolic factors to reduce future cardiovascular risk 3
- Women with early-onset preeclampsia (delivery before 32 weeks), stillbirth, or fetal growth retardation are at highest risk 3