What is the recommended antihypertensive medication for a 28-year-old female with chronic hypertension (high blood pressure) taking lisinopril (Angiotensin-Converting Enzyme inhibitor) who is trying to conceive?

Antihypertensive Medication Management for a Woman Trying to Conceive

Lisinopril must be discontinued immediately and switched to labetalol, methyldopa, or extended-release nifedipine before conception, as ACE inhibitors are contraindicated in pregnancy due to severe fetotoxicity. 1, 2

Why ACE Inhibitors Must Be Avoided

• ACE inhibitors like lisinopril cause severe fetal damage, particularly in the second and third trimesters 1
• Even first trimester exposure warrants close monitoring with fetal ultrasound if taken inadvertently 1
• These medications are strictly contraindicated for women planning pregnancy due to:
  • Risk of fetal renal failure
  • Risk of fetal malformations
  • Associated with high perinatal mortality (97/1000) 3

Recommended First-Line Alternatives

1. Labetalol:

   • First-line agent with established safety during pregnancy 2
   • Comparable efficacy to methyldopa 1
   • Can be administered intravenously if severe hypertension develops 1
   • Low transfer to breast milk (relative infant dose 3.6%) if breastfeeding is planned 2

2. Methyldopa:

   • Well-established safety profile with long-term infant follow-up data (7.5 years) 1
   • Traditional first-line agent for hypertension in pregnancy 2

3. Extended-release nifedipine:

   • Long-acting calcium channel blocker safe for use in pregnancy 2
   • Effective alternative if beta-blockers are contraindicated

Blood Pressure Targets

• Pre-conception and during pregnancy: maintain BP <140/90 mmHg 2
• Do not lower diastolic BP below 80 mmHg to maintain uteroplacental perfusion 2
• Current evidence supports controlling BP to 110-135/85 mmHg during pregnancy to:
  • Reduce risk of accelerated maternal hypertension
  • Minimize impairment of fetal growth 1

Special Considerations

• Women with chronic hypertension have increased risk for:

  • Preeclampsia
  • Fetal growth restriction 2
  • Placental abruption
  • Preterm birth 1

• The CHAP trial demonstrated that active treatment of chronic hypertension in pregnancy (target <140/90 mmHg) reduced the composite outcome of preeclampsia with severe features, medically indicated preterm birth, placental abruption, and fetal/neonatal death (30.2% vs 37.0%) 1

Medication Switching Protocol

1. Discontinue lisinopril immediately
2. Start alternative therapy (labetalol, methyldopa, or nifedipine)
3. Monitor BP closely during transition (weekly at minimum) 2
4. Adjust dosage to maintain target BP <140/90 mmHg
5. Continue medication throughout pregnancy with regular monitoring

Monitoring During Pregnancy

• Regular BP monitoring (at least weekly in stable patients) 2
• Monitor for development of proteinuria (sign of preeclampsia)
• Fetal growth assessment via ultrasound
• Consider low-dose aspirin (75-100 mg/day) prophylactically if history of early-onset preeclampsia 1, 2

Pitfalls to Avoid

1. Delayed medication switch: ACE inhibitors must be discontinued before conception, not just after pregnancy is confirmed
2. Inadequate BP control: Untreated hypertension increases risk of adverse maternal and fetal outcomes
3. Excessive BP lowering: Diastolic BP <80 mmHg may compromise uteroplacental perfusion
4. Using atenolol: Associated with fetal growth restriction; avoid in pregnancy 2, 4
5. Using diuretics: Not recommended for routine BP management in pregnancy 1

By following these guidelines, the 28-year-old patient can safely manage her hypertension while trying to conceive and throughout pregnancy, significantly reducing risks to both herself and her future baby.