Chronic hypertension in pregnancy

Definition & Diagnosis - Pressure Points

• Definition: Hypertension (SBP ≥ 140 or DBP ≥ 90 mmHg) that is:
  • Present before pregnancy.
  • Diagnosed before 20 weeks of gestation.
  • Persists > 12 weeks postpartum.
• Diagnostic Criteria:
  • BP ≥ 140/90 mmHg on 2 occasions at least 4 hours apart.
• Baseline Evaluation:
  • Assess for end-organ damage & risk of superimposed preeclampsia.
  • Labs: CBC, CMP (LFTs, Creatinine), Urinalysis, Urine Protein/Creatinine ratio.

⭐ Women with chronic hypertension have a 10-25% risk of developing superimposed preeclampsia.

Maternal & Fetal Risks - A Double Danger

Chronic hypertension creates a hostile uterine environment, jeopardizing both mother and fetus through vascular and placental compromise.

• Maternal Risks:

  • Superimposed Preeclampsia: Develops in ~25% of cases.
  • Placental Abruption: Acute, life-threatening separation.
  • ↑ rates of Cesarean Delivery.
  • End-organ damage: Stroke, pulmonary edema, renal failure.
  • Postpartum hemorrhage.

• Fetal Risks:

  • Fetal Growth Restriction (FGR): Resulting from uteroplacental insufficiency.
  • Preterm Birth: Often iatrogenic.
  • Oligohydramnios
  • Intrauterine fetal demise (IUFD).

⭐ Superimposed preeclampsia is the most common and feared maternal complication, dramatically worsening prognosis for both mother and baby. It's a key sentinel event to monitor for.

Antenatal Management - The Control Tower

• Goal: Maintain blood pressure < 140/90 mmHg.
• Pharmacotherapy:
  • 1st Line: Labetalol, Nifedipine (long-acting), Methyldopa.
  • 📌 Mnemonic: Hypertensive Moms Love Nifedipine.
  • ⚠️ AVOID: ACE inhibitors, ARBs, renin inhibitors (teratogenic).
• Preeclampsia Prophylaxis:
  • Low-dose Aspirin (81 mg/day) initiated between 12-16 weeks gestation.
• Fetal Surveillance:
  • Serial growth ultrasounds and antenatal testing (NST, BPP) starting in the 3rd trimester.

⭐ Delivery for well-controlled chronic hypertension is recommended at ≥38 0/7 weeks. If severe or refractory, delivery may occur earlier after maternal stabilization.

Delivery & Postpartum - The Final Lap

• Delivery Timing: Guideline-driven, balancing maternal risk & neonatal maturity.
  • Well-controlled cHTN: 38 0/7 - 39 6/7 wks.
  • Poorly controlled / superimposed preeclampsia: Consider delivery at ≥37 0/7 wks.
• Intrapartum Management:
  • Target BP <160/110 mmHg.
  • IV Labetalol or Hydralazine for severe hypertension.
• Postpartum Care:
  • Continue close BP monitoring for 72 hrs inpatient.
  • Breastfeeding-safe meds: Labetalol, Nifedipine.
  • Re-evaluate therapy 2 weeks postpartum.

⭐ High-Yield: Blood pressure often peaks 3-6 days postpartum, a period of high vulnerability. Schedule a follow-up BP check 7-10 days after discharge.

High-Yield Points - ⚡ Biggest Takeaways

• Defined as BP ≥140/90 mmHg before pregnancy or at <20 weeks gestation.
• Significantly increases risk for superimposed preeclampsia, placental abruption, and fetal growth restriction (FGR).
• First-line medications safe in pregnancy are Labetalol, Nifedipine, and Methyldopa.
• ACE inhibitors and ARBs are strictly contraindicated due to severe fetal toxicity.
• The management goal is to maintain BP <140/90 mmHg to reduce maternal and fetal complications.
• Delivery is typically planned at 38-39 weeks for well-controlled hypertension without complications.