How are the common systems used to classify hypertensive disorders during pregnancy?

Updated: Feb 22, 2019
  • Author: Matthew R Alexander, MD, PhD; Chief Editor: Eric H Yang, MD  more...
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Answer

Hypertensive disorders during pregnancy are classified into the four following categories, as recommended by the 2000 National High Blood Pressure Education Program Working Group on High Blood Pressure in Pregnancy [141] :

  • Chronic hypertension

  • Preeclampsia-eclampsia

  • Preeclampsia superimposed on chronic hypertension

  • Gestational hypertension (transient hypertension of pregnancy or chronic hypertension identified in the latter half of pregnancy); this terminology is preferred over the older but widely used term pregnancy-induced hypertension (PIH) because it is more precise.

However, the JNC 7 categorizes hypertensive disorders during pregnancy as follows (see Table 7, below) [5] :

  • Chronic hypertension
  •  Preeclampsia
  • Chronic hypertension with superimposed preeclampsia
  • Gestational hypertension
  • Transient hypertension

The 2013 American College of Obstetricians and Gynecologists (ACOG) uses a classification system similar to that of JNC 7. [142]

In 2014, the Society of Obstetricians and Gynecologists of Canada (SOGC) released revised guidelines that classify hypertension in pregnancy as follows [138] :

  • Preexisting hypertension
  • Gestational hypertension
  • Preeclampsia
  • Other hypertensive effects (transient hypertensive effect, white-coat hypertensive effect, masked hypertensive effect)

Table 7. JNC 7 Classification of Hypertensive Disorders in Pregnancy (Open Table in a new window)

Classification

Characteristics

Chronic hypertension

SBP ≥140 mm Hg or DBP ≥90 mm Hg, present pre-pregnancy or before 20 weeks’ gestation and persisting >12 weeks postpartum

Preeclampsia

SBP ≥140 mm Hg or DBP ≥90 mm Hg with proteinuria (>300 mg/24 h) that develops >20 weeks’ gestation;

Can progress to eclampsia

More common in nulliparous women, multiple gestation, women with hypertension ≥4 years, family history of preeclampsia, previous hypertension in pregnancy, and renal disease

Chronic hypertension with superimposed preeclampsia

New-onset proteinuria after 20 weeks’ gestation in a hypertensive woman or

In a woman with hypertension and proteinuria before 20 weeks’ gestation:

• Sudden 2- to 3-fold increase in proteinuria

• Sudden increase in BP

• Thrombocytopenia

• Elevated AST or ALT levels

Gestational hypertension

Temporary diagnosis

Hypertension without proteinuria after 20 weeks’ gestation

May be a preproteinuric phase of preeclampsia or a recurrence of chronic hypertension that abated in mid-pregnancy

May lead to preeclampsia

Severe cases may cause higher rates of premature delivery and growth retardation relative to mild preeclampsia

Transient hypertension

Diagnosis made retrospectively

BP returns to normal by 12 weeks postpartum

May recur in subsequent pregnancies

Predictive of future primary hypertension

ALT = alanine aminotransferase; AST = aspartate aminotransferase; BP = blood pressure; DBP = diastolic BP; SBP = systolic BP


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