What are the criteria for induction of labor in a pregnant woman with gestational hypertension?

Criteria for Induction of Labor in Gestational Hypertension

Women with gestational hypertension should be delivered at 37 weeks and 0 days gestation, or earlier if they develop severe hypertension requiring three antihypertensive classes, progressive thrombocytopenia, worsening liver or kidney function, pulmonary edema, severe neurological symptoms, or nonreassuring fetal status. 1

Gestational Age-Based Delivery Criteria

At 37 Weeks Gestation or Beyond

• Routine delivery is recommended at 37 weeks and 0 days gestation for all women with gestational hypertension, regardless of severity. 1
• This timing prevents severe hypertensive complications without increasing cesarean delivery risk. 2

Before 37 Weeks (Preterm Delivery Indications)

Delivery should occur before 37 weeks if any of the following maternal or fetal complications develop:

Maternal Indications:

• Repeated episodes of severe hypertension (≥160/110 mmHg) despite treatment with three classes of antihypertensive medications 1
• Progressive thrombocytopenia (falling platelet count) 1
• Progressively abnormal liver enzyme tests 1
• Progressively abnormal renal function tests 1
• Pulmonary edema 1
• Severe intractable headache 1
• Repeated visual scotomata (visual disturbances) 1
• Convulsions/eclampsia 1

Fetal Indications:

• Nonreassuring fetal status on monitoring 1
• Severe fetal growth restriction with abnormal Doppler studies 1

Blood Pressure Management Prior to Delivery

Treatment Thresholds

• Initiate antihypertensive therapy when blood pressure consistently reaches ≥140/90 mmHg in clinic (or ≥135/85 mmHg at home). 1
• Target diastolic blood pressure of 85 mmHg and systolic blood pressure of 110-140 mmHg. 1
• Reduce or discontinue antihypertensives if diastolic blood pressure falls below 80 mmHg to avoid compromising uteroplacental perfusion. 1

Severe Hypertension Management

• Blood pressure ≥160/110 mmHg requires urgent treatment in a monitored setting. 1
• First-line agents for acute severe hypertension include oral nifedipine (immediate-release) or intravenous labetalol or hydralazine. 1
• Treatment must be initiated within 30-60 minutes of the first severe reading. 3

Monitoring Requirements Before Delivery Decision

Maternal Monitoring

• Blood pressure monitoring at every visit 1
• Repeated assessments for new-onset proteinuria if not already present 1
• Clinical assessment including evaluation for clonus 1
• Laboratory tests at minimum twice weekly: complete blood count (hemoglobin, platelets), liver function tests, renal function tests including creatinine and uric acid 1

Fetal Monitoring

• Initial assessment to confirm fetal well-being upon diagnosis 1
• Serial fetal surveillance with ultrasound if fetal growth restriction is present 1
• Continuous electronic fetal heart rate monitoring when delivery is being considered 4

Important Clinical Considerations

Hospitalization Criteria

• Women with gestational hypertension should be assessed in hospital when first diagnosed. 1
• Some may be managed as outpatients once their condition is stable and they can reliably report problems and monitor their blood pressure at home. 1
• All women with severe features require hospitalization in centers with adequate maternal and neonatal intensive care resources. 1

Magnesium Sulfate Administration

• Magnesium sulfate should be administered for seizure prophylaxis in women with gestational hypertension who have proteinuria AND severe hypertension (≥160/110 mmHg), or any neurological signs or symptoms. 1, 4
• Do not administer magnesium sulfate concurrently with calcium channel blockers due to risk of severe hypotension. 1, 5

Common Pitfalls to Avoid

• Do not delay delivery beyond 37 weeks in women with gestational hypertension, as expectant management increases the risk of superimposed preeclampsia (approximately 19% risk) and eclampsia without reducing cesarean delivery rates. 2
• Do not use methyldopa for urgent blood pressure reduction—it is ineffective for acute management. 1
• Avoid NSAIDs postpartum in women with gestational hypertension as they can worsen hypertension and impair renal function. 5
• Blood pressure may worsen between days 3-6 postpartum, requiring continued vigilance even after delivery. 5