Hypertension in Pregnancy

1. See Also
   1. Pregnancy Induced Hypertension
   2. PIH Prophylaxis
   3. Mild PIH Management
   4. Severe PIH Management
   5. PIH Blood Pressure Management
2. Definition
   1. Chronic Hypertension in Pregnancy
      1. Chronic Hypertension that extends into pregnancy without Preeclampsia
   2. Gestational Hypertension
      1. Hypertension in Pregnancy with onset beyond 20 weeks gestation and NO Proteinuria
3. Complications: Pregnancy Related
   1. Superimposed Preeclampsia
   2. Placental Abruption
   3. Intrauterine Growth Retardation
4. Risk Factors: Superimposed Preeclampsia Risk Factors
   1. Age 35 years or higher
   2. Antihypertensive needed for Blood Pressure control
   3. History of prior pregnancy complications
      1. Preeclampsia
      2. Untrauterine growth retardation
      3. Intrauterine Fetal Demise
   4. Comorbid conditions
      1. Diabetes Melllitus
      2. Systemic Lupus Erythematosus
      3. Chronic cardiopulmonary disease
      4. Renal disease
   5. Abnormal labs
      1. Serum Creatinine >1.0 mg/dl
      2. Proteinuria >300 mg/24 hours
      3. Phopholipid Antibody positive
5. Monitoring
   1. Initial evaluation (at time of diagnosis)
      1. Estimate Fetal Growth
      2. Estimate amniotic fluid index (AFI)
      3. Non-Stress Test (NST)
      4. Biophysical Profile (BPP) if NST not reactive
      5. Further evaluation if BPP <8
   2. Repeat Testing
      1. Ultrasound every 4 weeks starting at 28 weeks gestation
      2. Other testing as indicated for significant maternal status changes
6. Management
   1. See PIH Blood Pressure Management
   2. See Anti-Hypertensive Medications in Pregnancy
   3. Hypertension therapy during pregnancy does not reduce pregnancy complications
      1. See antihypertensives below
      2. Aspirin does not lower Preeclampsia risk
         1. Caritis (1998) N Engl J Med
      3. Low sodium diet shows no benefit
      4. Minimizing weight gain shows no benefit
      5. Exercise restriction offers no benefit
7. Management: Anti-hypertensives
   1. Goal: Lower Systolic Blood Pressure to <150/100 (much higher than non-pregnant goal)
   2. Anti-hypertensives are not indicated for mild to moderate Chronic Hypertension in Pregnancy
      1. Treatment of BP <150/100 does not reduce risk to fetus or prevent Preeclampsia
         1. Antihypertensives benefit mother only (these do not reduce pregnancy complications)
         2. van Dadelszen (2000) Lancet
      2. Aggressive lowering of Blood Pressure may result in adverse fetal outcomes
      3. Severe chronic Hypertension (consistently >150-180/100-110) should be treated
      4. (2001) Obstet Gynecol 98(1 suppl): 177-85
   3. Antihypertensive used in pregnancy
      1. Alpha methyldopa 500 mg PO bid (up to 2 grams bid)
      2. Labetolol 200 mg PO bid (up to 1200 mg bid)
      3. Felodipine 5 mg PO daily (up to 20 mg daily)
      4. Hydrochlorothiazide
         1. Not usually initiated in pregnancy due to volume depletion
         2. May be continued if on pre-pregnancy - consult with local expert opinion
      5. Nifedipine XL 30 mg PO bid (up to 120 mg daily)
      6. Hydralazine 10 mg PO tid (up to 25 mg tid)
8. Precautions: Chronic Hypertension in Pregnancy
   1. Observe for superimposed Preeclampsia on chronic Hypertension
   2. High index of suspicion if maked Blood Pressure increase or new onset Proteinuria
9. Precautions: Gestational Hypertension
   1. Preeclampsia will develop in 50% of those with Gestational Hypertension onset 24-35 weeks
      1. Barton (2001) Am J Obstet Gynecol 184(5): 979-83
   2. Severe Gestational Hypertension is associated with worse outcomes than mild PIH
      1. Treat with same management protocol as Severe Preeclampsia
      2. Buchbinder (2002) Am J Obstet Gynecol 186:66-71
10. References
    1. (2001) Obstet Gynecol 98(1 suppl): 177-85
    2. Leeman (2008) Am Fam Physician 78: 93-100