What are the American College of Obstetricians and Gynecologists (ACOG) guidelines for induction of labor in a woman with gestational hypertension?

ACOG Guidelines for Induction of Labor in Gestational Hypertension

For women with gestational hypertension at term, induction of labor should be offered at 37 weeks of gestation to reduce maternal complications, particularly progression to preeclampsia and severe hypertensive disease, without increasing cesarean delivery rates. 1

Timing of Delivery by Gestational Age

At 37 Weeks (Recommended Threshold)

• Most international guidelines, including those aligned with ACOG principles, recommend delivery at 37 weeks for gestational hypertension 1
• Seven of twelve guidelines in a systematic review specified delivery at exactly 37 weeks for gestational hypertension 1
• Induction at 37 weeks prevents maternal complications without increasing cesarean delivery risk compared to expectant management 1, 2

Between 37-39 Weeks (Alternative Approaches)

• Some guidelines recommend discussing delivery from 37 weeks onward, allowing shared decision-making 1
• Three guidelines recommend delivery between 38-39 weeks for gestational hypertension 1
• Induction at 38 weeks specifically reduces severe maternal complications (adjusted OR 0.45) compared to delivery at ≥39 weeks in nulliparous women 3

Special Consideration: If on Antihypertensive Therapy

• One guideline recommends delivery by 37 weeks if the woman requires antihypertensive medications, or by 38 weeks if blood pressure remains controlled without medication 1

Maternal Benefits of Induction at Term

Prevention of Hypertensive Complications

• Induction at 37 weeks reduces the incidence of hypertensive disorders from 14.1% to 9.1% (RR 0.64) 1
• Expectant management beyond 37 weeks carries a 19% risk of developing superimposed preeclampsia 4
• Women managed expectantly face risks of eclampsia (0.6-0.7%) and severe hypertension requiring urgent intervention 4

Cesarean Delivery Rates

• Induction at 37-38 weeks does not increase cesarean delivery rates compared to expectant management 3, 2
• In nulliparous women with gestational hypertension, cesarean rates were 26.9% at 37 weeks, 19.7% at 38 weeks, and 29.9% at ≥39 weeks (no significant difference) 3
• Induction at 38 weeks may actually reduce cesarean risk (adjusted RR 0.74) compared to expectant management 4

Neonatal Safety Considerations

Neonatal Morbidity

• Composite neonatal morbidity is similar whether delivery occurs at 37,38, or ≥39 weeks in women with gestational hypertension 3
• Neonatal care unit admission rates are comparable across early term gestational ages (approximately 7% at both 38 and 39 weeks) 5
• The ARRIVE trial demonstrated no difference in primary neonatal outcomes between elective induction at 39 weeks versus expectant management in low-risk nulliparous women 1

Respiratory Concerns

• While respiratory distress syndrome increases from 1% at 37 weeks to potentially 10% at 34 weeks in preterm gestations, this is not a significant concern at 37+ weeks 6

Prerequisites for Safe Induction at Term

Dating Confirmation (Critical)

• All women must have gestational age confirmed by early ultrasonography before offering elective induction 1
• For women certain of their last menstrual period, dating ultrasound must be performed before 21 weeks 1
• For uncertain last menstrual period, only first-trimester ultrasound dating is acceptable 1
• This prevents iatrogenic early term or preterm delivery, as early term neonates (37 0/7 to 38 6/7 weeks) have increased respiratory morbidity 1

Patient Eligibility

• Singleton pregnancy 5
• Gestational hypertension without severe features initially 1
• No contraindications to vaginal delivery 1

Management During Expectant Monitoring (If Chosen)

Surveillance Requirements

• Enhanced fetal and maternal surveillance if expectant management is pursued 1
• More than half of women managed expectantly will ultimately require induction later in gestation (56.8-57.8%) 4
• Blood pressure monitoring at minimum every 4-6 hours during hospitalization 7

Indications for Immediate Delivery Regardless of Gestational Age

• Severe hypertension (≥160/110 mmHg sustained for >15 minutes) requires immediate treatment and consideration for delivery 1, 7
• Development of preeclampsia with severe features 1
• Fetal distress or intrauterine growth restriction 1
• Maternal symptoms: visual disturbances, severe headache, epigastric pain 1
• Laboratory abnormalities: thrombocytopenia, elevated liver enzymes, renal dysfunction 1, 7

Shared Decision-Making Framework

Counseling Points for Patients

• Both induction at 37-38 weeks and expectant management until 39 weeks are reasonable options 1, 5
• Induction reduces risk of progression to preeclampsia and severe hypertension 1
• Cesarean delivery rates are not increased with early term induction 3, 4
• Neonatal outcomes are similar across the 37-39 week range 3, 5
• Expectant management requires close surveillance and carries 19% risk of developing preeclampsia 4

Patient Preference Considerations

• Some women prefer avoiding spontaneous labor and having a planned delivery 1
• Others prefer waiting for spontaneous labor onset 1
• High satisfaction rates were reported among trial participants who underwent elective induction, though this may not be generalizable 1

Common Pitfalls to Avoid

Dating Errors

• Never offer elective induction without confirmed early ultrasound dating - this is the most critical safety measure 1
• Do not rely on last menstrual period alone for dating 1

Resource Considerations

• Ensure adequate labor and delivery capacity before implementing routine early term induction 1
• Women with medical indications for delivery take priority over elective inductions 1
• Adequate nursing, anesthesia, and physician staffing must be available 1

Blood Pressure Management

• Do not withhold antihypertensive therapy if blood pressure reaches severe range (≥160/110 mmHg) 1
• First-line agents for severe hypertension include IV labetalol, oral nifedipine, or IV hydralazine 1
• Avoid renin-angiotensin system blockers, atenolol, and diuretics (except for specific indications) 1

Postpartum Vigilance

• Blood pressure typically rises in the first 3-6 days postpartum - hypertension may worsen or appear de novo after delivery 1, 7
• Continue or initiate antihypertensive therapy postpartum as needed 1
• Switch methyldopa to alternative agents postpartum due to risk of postpartum depression 1

Algorithm for Decision-Making

1. Confirm diagnosis of gestational hypertension (new-onset hypertension ≥140/90 mmHg after 20 weeks without proteinuria or other preeclampsia features) 1

2. Verify gestational age with early ultrasound documentation 1

3. At 36-37 weeks: Counsel patient on options:

   • Induction at 37 0/7 to 37 6/7 weeks (reduces maternal complications, no increase in cesarean delivery) 1, 3
   • Induction at 38 0/7 to 38 6/7 weeks (lowest maternal morbidity in some studies) 3
   • Expectant management until 39 weeks with enhanced surveillance 1, 5

4. If expectant management chosen: Monitor closely for:

   • Severe hypertension (≥160/110 mmHg) → immediate delivery 1, 7
   • Symptoms of preeclampsia → immediate delivery 1
   • Fetal compromise → immediate delivery 1

5. Maximum gestational age: Deliver by 39 weeks regardless of blood pressure control 1