Hypertensive disorders complicate 5 to 10 percent of all pregnancies, and together they form one member of the deadly triad, along with hemorrhage and infection, that contribute greatly to maternal morbidity and mortality rates. With hypertension, the preeclampsia syndrome, either alone or superimposed on chronic hypertension, is the most dangerous. As subsequently discussed, new-onset nonproteinuric hypertension during pregnancy—termed gestational hypertension—is followed by signs and symptoms of preeclampsia almost half the time, and preeclampsia is identified in 3.9 percent of all pregnancies (Martin and colleagues, 2009). The World Health Organization systematically reviews maternal mortality worldwide (Khan and colleagues, 2006). In developed countries, 16 percent of maternal deaths were due to hypertensive disorders. This percentage is greater than three other leading causes: hemorrhage—13 percent, abortion—8 percent, and sepsis—2 percent. In the United States from 1991 to 1997, Berg and colleagues (2003) reported that almost 16 percent of 3201 maternal deaths were from complications of pregnancy-related hypertension. Importantly, Berg and co-workers (2005) later reported that over half of these hypertension-related deaths were preventable.
How pregnancy incites or aggravates hypertension remains unsolved despite decades of intensive research. Indeed, hypertensive disorders remain among the most significant and intriguing unsolved problems in obstetrics.
The term gestational hypertension as used in previous editions of this book was chosen by Dr. Jack Pritchard to describe any new-onset uncomplicated hypertension during pregnancy when no evidence of the preeclampsia syndrome was apparent. Unfortunately, confusion arose by some using the term for both gestational hypertension and preeclampsia. We have thus adopted the schema of the Working Group of the NHBPEP—National High Blood Pressure Education Program (2000).
The Working Group classification of hypertensive disorders complicating pregnancy as shown in Table 34-1 describes four types of hypertensive disease:
Gestational hypertension—formerly termed pregnancy-induced hypertension. If preeclampsia syndrome does not develop and hypertension resolves by 12 weeks postpartum, it is redesignated as transient hypertension
Preeclampsia and eclampsia syndrome
Preeclampsia syndrome superimposed on chronic hypertension
Table 34-1. Diagnosis of Hypertensive Disorders Complicating Pregnancy |Favorite Table|Download (.pdf)
Table 34-1. Diagnosis of Hypertensive Disorders Complicating Pregnancy
- Systolic BP ≥140 or diastolic BP ≥90 mm Hg for first time during pregnancy
- No proteinuria
- BP returns to normal before 12 weeks postpartum
- Final diagnosis made only postpartum
- May have other signs or symptoms of preeclampsia, for example, epigastric discomfort or thrombocytopenia
- BP ≥140/90 mm Hg after 20 weeks' gestation
- Proteinuria ≥300 mg/24 hours or ≥ 1+ dipstick
Increased certainty of preeclampsia:
- BP ≥160/110 mm Hg
- Proteinuria 2.0 g/24 hours or ≥ 2+ dipstick
- Serum creatinine >1.2 mg/dL unless known to be previously elevated
- Platelets < 100,000/μL
- Microangiopathic hemolysis—increased LDH
- Elevated serum transaminase levels—ALT or AST
- Persistent headache or other cerebral or visual disturbance
- Persistent epigastric pain
- Seizures that cannot be attributed to other causes in a woman with preeclampsia...