What is the management plan for a 36-year-old pregnant woman with chronic hypertension (HTN) at 21+2 weeks gestation, currently taking labetalol (200mg twice daily) and aspirin?

Management of Chronic Hypertension in Pregnancy at 21+2 Weeks

Continue the current regimen of labetalol 200mg twice daily and aspirin until 36 weeks, as the patient's blood pressure is well-controlled at 113/72 mmHg and she meets criteria for aspirin prophylaxis due to chronic hypertension. 1, 2, 3

Blood Pressure Management

Current Status Assessment

• The patient's BP of 113/72 mmHg is excellent and below the target of <130/85 mmHg, indicating optimal control on the current labetalol dose 2
• No adjustment to labetalol is needed at this time, as the BP is well within therapeutic range 2

Labetalol Dosing Considerations

• The current dose of 200mg twice daily is appropriate and within the standard maintenance range of 200-400mg twice daily 4
• If BP control becomes inadequate, labetalol can be titrated in 100mg increments every 2-3 days, up to a maximum of 2400mg daily 4
• Consider switching to three-times-daily dosing if side effects (nausea, dizziness) occur, as labetalol metabolism accelerates during pregnancy 1, 4
• The European Society of Cardiology notes that labetalol dosing may need adjustment to TID or QID due to accelerated drug metabolism during pregnancy 1

Blood Pressure Targets and Monitoring

• Maintain BP between 110-135/80-85 mmHg to reduce risk of maternal complications while preserving uteroplacental perfusion 2, 5
• Reduce or cease antihypertensive therapy if diastolic BP falls below 80 mmHg to avoid compromising fetal perfusion 2
• Monitor BP at each midwife visit, with particular attention to standing BP to assess for postural hypotension 4

Aspirin Prophylaxis

Current Indication and Duration

• Continue aspirin 81mg daily until 36 weeks as planned, given chronic hypertension qualifies as a high-risk factor for preeclampsia 3, 6
• The American College of Obstetricians and Gynecologists recommends aspirin continuation until delivery for women with chronic hypertension 3, 6
• Discontinuation at 36 weeks is reasonable based on recent evidence showing safety of earlier discontinuation in low-risk patients, though guidelines traditionally recommend continuation until delivery 7

Aspirin Dosing Considerations

• The standard 81mg daily dose may be suboptimal; emerging evidence suggests doses >100mg (such as 150-162mg) initiated before 16 weeks are more effective at preventing preeclampsia 8
• However, since the patient is already at 21 weeks and on aspirin, continue the current dose rather than escalating at this gestational age 8

Symptom Assessment and Red Flags

Current Symptoms Requiring Evaluation

• Lower abdominal pain with walking warrants assessment for preterm labor, placental abruption, or musculoskeletal causes at tomorrow's midwife visit 2
• Occasional vaginal discharge is common but should be evaluated to exclude infection or membrane rupture 2

Warning Signs to Monitor

• Severe-range hypertension (BP >159/109 mmHg) requires urgent treatment within 30-60 minutes to prevent maternal stroke and fetal complications 1
• Headaches, visual changes, right upper quadrant pain, or sudden swelling suggest preeclampsia and require immediate evaluation 1, 5
• Decreased fetal movements, vaginal bleeding, or persistent abdominal pain warrant urgent assessment 2

Medication Safety and Contraindications

Labetalol Precautions

• Labetalol is contraindicated in reactive airway disease/asthma, second or third-degree AV block, and maternal systolic heart failure 2
• Monitor for bronchoconstriction, bradycardia, postural hypotension, and masking of hypoglycemia 2
• No teratogenicity has been reported with labetalol use in pregnancy 1

Medications to Avoid

• ACE inhibitors and angiotensin receptor blockers are absolutely contraindicated due to fetal renal dysgenesis and fetotoxicity 5
• Atenolol should not be used due to risk of fetal growth restriction 1
• Avoid hydralazine IV as first-line therapy due to increased perinatal adverse effects 5

Follow-up Plan

Immediate Actions

• Issue repeat prescriptions for labetalol 200mg twice daily and aspirin 81mg daily 4, 3
• Ensure midwife evaluates lower abdominal pain and vaginal discharge at tomorrow's visit 2

Ongoing Monitoring

• Continue regular midwife visits with BP monitoring at each appointment 2
• Maintain obstetric specialist oversight as currently established 1
• If BP rises to ≥140/90 mmHg on two separate occasions, increase labetalol dose by 100mg increments 2, 4

Postpartum Considerations

• Plan transition to once-daily agents postpartum (nifedipine, amlodipine, or enalapril) as labetalol is less effective postpartum and associated with higher readmission rates 1
• All agents mentioned are compatible with breastfeeding 1