hypertension during pregnancy

Introduction

180/110 > BP > 140/90 is considered mild

Etiology

• no strong evidence supports a causal effect of vitamin D status on gestational hypertension or pre-eclampsia

Epidemiology

• prevalence 1.5% of pregnant women

Clinical manifestations

• gestational hypertension (HTN)
  • develops at 20 weeks of gestation or later
  • not associated with proteinuria or other features of preeclampsia
  • resolves within 12 weeks of delivery
• hypertension during the 1st 20 weeks of gestation suggests chronic hypertension present prior to pregnancy
• chronic hypertension continues > 12 weeks post-partum

Complications

• preeclampsia:
  • women with chronic hypertension are at increased risk
    • RR = 8
  • controlling BP does NOT reduce the risk
• pheochromocytosis & renovascular hypertension associated with poor maternal & fetal prognosis
• women with primary hyperaldosteronism have relatively uncomplicated pregnancies
• diastolic BP of 76-82 mm Hg throughout pregnancy associated with 6-fold risk of developing the metabolic syndrome, relative diastolic BP of 63-65 mm Hg
• increased long-term risk for post-pregnancy hypertension
  • black women more likely than white women to be hypertensive postpartum
  • controlling BP does NOT reduce the risk
• hypertension during pregnancy associated with increased risk of cognitive impairment 15 years later
• increased mortality later life from
  • diabetes mellitus (RR=2.8)
  • ischemic heart disease (RR=2.2)
  • stroke (RR=1.9)
  • Alzheimer disease (RR=3.4)
• hypertension during pregnancy associated with increased risk for autism & attention-deficit hyperactivity disorder among offspring
• increased risk for hypercholesterolemia (RR=1.3)

Management

• treat hypertension during pregnancy if BP > 140/90 before pregnancy or before 20 weeks gestation or persists > 12 weeks postpartum
  • formerly treatment indicated for persistent systolic BP >= 160 mm Hg or diastolic BP >= 110 mm Hg in women with chronic hypertension
  • treatment of chronic hypertension (<160/110 mm Hg) is not associated with improved fetal outcomes
  • persistence of BP > 160/110 mm Hg indicates severe HTN
  • goal is BP < 150/100; 120-159/80-109 mm Hg
  • use lower threshold if chronic renal failure
  • outcomes better with treatment to target of < 140/90 mm Hg
  • tight control of blood pressure (target diastolic BP of 85 mm Hg) is not associated with increased perinatal risk or major benefits
• treatment
  • labetolol (first line)
  • alpha-methyldopa (Aldomet)
  • hydralazine#
  • nifedipine*
  • diuretics are OK
    • diuretics may induce oligohydramnios if initiated during pregnancy
  • ACE inhibitors, ARBs are CONTRAINDICATED
  • atenolol is CONTRAINDICATED
• vitamin C & vitamin E of no benefit in preventing complications
• prophylaxis for pre-eclampsia in high-risk patients
  • magnesium sulfate 4-6 g bolus, followed by 2 g per hour; continue for at least 24 hours after delivery
  • low dose aspirin 75-150 mg/day to inhibit formation of TxA2

* alternative agent (other calcium channel blockers ok)

# adverse effects (headache, nausea, vomiting mimick worsening preeclampsia; hydralazine associated with higher risk of adverse outcomes than nifedipine or labetolol

More general terms

• pregnancy disorder; obstetric disorder; pregnancy complication
• hypertension (HTN, high blood pressure, HBP)

More specific terms

• early onset hypertension with severe exacerbation in pregnancy
• pregnancy-induced hypertension; gestational hypertension (PIH)

Additional terms

• eclampsia