Print: Chapter 34. Hypertensive Disorders in Pregnancy

Hypertensive Disorders in Pregnancy: Introduction Hypertensive disorders complicating pregnancy are common and form one of the deadly triad, along with hemorrhage and infection, that contribute greatly to maternal morbidity and mortality. In 2001, according to the National Center for Health Statistics, gestational hypertension was identified in 150,000 women, or 3.7 percent of pregnancies (Martin and colleagues, 2002). Importantly, Berg and colleagues (2003) reported that almost 16 percent of 3201 pregnancy-related deaths in the United States from 1991 to 1997 were from complications of pregnancy-related hypertension. These investigators also found that black women in this country are 3.1 times as likely to die from preeclampsia as white women. 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. To elucidate these, ongoing research is sponsored by the National Institutes of Child Health and Human Development (NICHD) and its Maternal–Fetal Medicine Units Network. Another important stimulus for research is the International Society for the Study of Hypertension in Pregnancy. The National Heart, Lung, and Blood Institute promotes research and coordination through the National High Blood Pressure Education Program (NHBPEP) and its Working Group for High Blood Pressure in Pregnancy. Terminology and Classification The term gestational hypertension is used now to describe any form of new-onset pregnancy-related hypertension. It was adopted by the Working Group of the NHBPEP (2000), which proposed a classification system based on clinical simplicity to guide management. The term was chosen to emphasize the causeand-effect connection between pregnancy and its unique form of hypertension—preeclampsia and eclampsia. It is also meant to be a working term that is purposefully vague, but it should convey that the development of hypertension in a previously normotensive pregnant woman should and must be considered potentially dangerous to both herself and her fetus. In the past several editions of Williams Obstetrics, the term pregnancy-induced hypertension was used. It was popularized by Dr. Jack Pritchard to convey the same principles, and it still is used by some interchangeably with gestational hypertension. The classification of hypertensive disorders complicating pregnancy by the Working Group of the NHBPEP (2000) is shown in Table 34–1. There are five types of hypertensive disease: