What is the best management approach for a 39-week pregnant Rh-negative woman with pregnancy-induced hypertension, who is not in labor and has a history of grand multiparity (G7P6)?

Management of 39-Week Rh-Negative Woman with Pregnancy-Induced Hypertension Not in Labor

Proceed with induction of labor at 39 weeks for this grand multipara with pregnancy-induced hypertension, as delivery at this gestational age optimizes maternal outcomes by preventing progression to severe disease while avoiding neonatal complications associated with prematurity. 1

Timing of Delivery

• Delivery at 39 weeks is optimal for gestational hypertension without features of preeclampsia, based on large retrospective studies, though this recommendation awaits confirmation from randomized trials. 1
• The HYPITAT trial demonstrated that induction of labor at or after 37 weeks in women with gestational hypertension reduces maternal complications without increasing cesarean delivery rates or neonatal complications. 2, 3
• For low-risk nulliparous women at 39 weeks, elective induction reduces both cesarean delivery rates (from 22.2% to 18.6%) and hypertensive disorders (from 14.1% to 9.1%). 4
• Grand multiparity (G7P6) favors successful vaginal delivery with induction, as multiparous women typically have more favorable cervical ripening and shorter labor courses compared to nulliparous women.

Blood Pressure Management Before and During Induction

• Treat blood pressure if consistently ≥140/90 mmHg, targeting diastolic BP of 85 mmHg to reduce likelihood of developing severe maternal hypertension and complications such as low platelets and elevated liver enzymes. 1
• Urgent treatment is required if BP reaches ≥160/110 mmHg, using oral nifedipine, intravenous labetalol, or hydralazine in a monitored setting. 1
• First-line oral agents for sustained control include extended-release nifedipine, labetalol, or methyldopa. 1, 5
• Reduce or cease antihypertensives if diastolic BP falls below 80 mmHg to avoid compromising uteroplacental perfusion. 1

Maternal Assessment and Monitoring

• Hospital assessment is mandatory when first diagnosed with gestational hypertension, though stable patients may subsequently be managed as outpatients if reliable for BP monitoring and symptom reporting. 1
• Monitor for progression to preeclampsia, which occurs in approximately 25% of gestational hypertension cases. 1
• Assess for severe hypertension (≥160/110 mmHg), proteinuria, neurological symptoms (headache, visual changes), right upper quadrant pain, and laboratory abnormalities (thrombocytopenia, elevated liver enzymes). 1
• Blood pressure monitoring should continue closely during labor and postpartum, as BP typically worsens between days 3-6 postpartum. 4

Fetal Monitoring

• Perform ultrasound assessment of fetal biometry, amniotic fluid volume, and umbilical artery Doppler at diagnosis. 1
• Repeat assessments at 2-week intervals if initial evaluation is normal, or more frequently if fetal growth restriction is suspected. 1

Rh Immunoprophylaxis Management

• Administer RhoGAM (Rh immune globulin) 300 mcg within 72 hours after delivery if the infant is Rh-positive, though it may still provide protection if given beyond 72 hours. 6
• If this patient received antenatal RhoGAM at 28 weeks (standard practice), she still requires postpartum dose unless delivery occurs within 3 weeks of the last dose AND there is no fetomaternal hemorrhage exceeding 15 mL of red blood cells. 6
• Perform Kleihauer-Betke test if large fetomaternal hemorrhage (>30 mL whole blood or >15 mL red cells) is suspected, as additional RhoGAM doses may be required. 6
• Calculate additional doses by dividing red blood cell volume by 15 mL; round up to next whole number of syringes. 6

Cervical Ripening Considerations

• Use cervical ripening agents if cervix is unfavorable, allowing at least 12 hours after completion before considering cesarean for "failed" induction. 4
• Grand multiparas typically have more favorable cervices and shorter induction times compared to nulliparous women, reducing the likelihood of cesarean delivery.

Critical Pitfalls to Avoid

• Do not delay delivery beyond 39 weeks in gestational hypertension, as the risk of progression to severe disease increases with expectant management. 1, 2
• Avoid NSAIDs for postpartum analgesia if any renal impairment exists, as they can worsen hypertension and kidney function. 7
• Do not use sublingual nifedipine due to risk of uncontrolled hypotension and potential maternal myocardial infarction. 5
• Avoid concurrent use of calcium channel blockers with magnesium sulfate due to risk of severe hypotension from synergistic effects. 7, 5
• Never administer RhoGAM intravenously or to the neonate—it must be given intramuscularly to the mother, preferably in the deltoid muscle. 6

Postpartum Management

• Continue blood pressure monitoring at least 4-6 times daily for the first 3 days postpartum. 4
• Switch from methyldopa to nifedipine or labetalol postpartum due to methyldopa's association with postpartum depression. 5, 4
• Most women can be discharged by day 5 if BP is stable, with home monitoring capability and follow-up within 1 week if still requiring antihypertensives. 7, 4
• All women require 3-month postpartum follow-up to ensure BP, urinalysis, and laboratory tests have normalized. 7, 4