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Preeclampsia and Hypertension in Pregnancy 

Maternal death complicates childbirth in approximately nine of 100,000 deliveries. The three leading causes of maternal death are pregnancy-induced hypertension, hemorrhage, and pulmonary embolism. Hypertension complicates an estimated 6 to 8% of all pregnancies. Hypertension is responsible for approximately 15% of maternal deaths. In addition, almost one-quarter of pregnant women require hospitalization for complications before delivery preeclampsia, pregnancy induced hypertension, preclampsia, preeclamsia, toxemia, preclampsea 

Hypertension in Pregnancy

Hypertension may be classified as chronic if it is recognized before 20 weeks of gestation or as pregnancy-induced if it occurs only in the second half of pregnancy. This separation is clinically useful because almost all hypertension occurring in the first half of pregnancy is a result of underlying chronic hypertension (essential hypertension or secondary hypertension due to hyperaldosteronism or pheochromocytoma) or renal disease. Hypertension developing in the second half of pregnancy is more complex and is the result of either a pregnancy-specific process or a complex interplay of pregnancy with renal disease or chronic hypertension resulting in exacerbation of hypertension preeclampsia, pregnancy induced hypertension, preclampsia, preeclamsia, toxemia, preclampsea

Normal pregnancy is characterized by a decrease in peripheral vascular resistance and, to a lesser extent, a decrease in blood pressure, which occur soon after conception. This decrease in vascular resistance is due to increased synthesis of vasodilatory prostaglandins, particularly prostacyclin, and endothelial-derived nitric oxide. These vasodilators also engender resistance to

Similarly, perinatal mortality increases when mean arterial pressure is greater than 82 mmHg at mid-pregnancy or greater than 92 mmHg at the beginning of the third trimester. Because a blood pressure of 120/80 mmHg represents a mean arterial pressure of 93 mmHg, it is apparent that

Preeclampsia

Preeclampsia, a life-threatening illness specific to pregnancy, is poorly understood. Major manifestations of preeclampsia include hypertension, edema, proteinuria, and seizures. The disease is termed eclampsia when seizures occur, but this distinction is not important because death due to cerebral hemorrhage or cardiac failure can occur in the absence of seizures. Preeclampsia is a fascinating disease because of its association with first pregnancies and 

Depending on the population surveyed, preeclampsia complicates between 5 and 22% of pregnancies. In addition to nulliparity, other risk factors for the development of preeclampsia include age greater than 40 years (advanced in terms of reproductive age), familial history of pregnancy-induced pregnancy hypertension, smoking, obesity, and 

Pregnancies complicated by fetal hydrops, multiple gestation, preexisting hypertension, antiphospholipid syndrome, renal disease, and vascular disease are also at increased risk of preeclampsia. The relative risk of preeclampsia developing in women with chronic renal disease is 20 to 1, and the risk of preeclampsia developing in women with essential hypertension is 

In these instances, preeclampsia affects multiparous, as well as nulliparous, women. Moreover, preeclampsia complicating these conditions may develop earlier than 32 weeks of gestation, whereas "usual" preeclampsia affecting nulliparous women develops in the third trimester (usually after 32 weeks of gestation). One should be alert to the possibility that preeclampsia occasionally presents as late as

The clinical manifestations of preeclampsia support the contention that this is a systemic disease. Hypertension is the most prominent feature of preeclampsia and may be severe. Hypertension

TABLE 1 -- Risk factors for the development of preeclampsia
Nulliparity
Age greater than 40 years (advanced age in reproductive terms)
Familial history of pregnancy-induced pregnancy hypertension
Obesity
Diabetes mellitus
Fetal hydrops
Multiple gestation
Hypertension
Renal disease
Antiphospholipid syndrome
Vascular disease

is caused by an increase in peripheral vascular resistance and is associated with overactivity of the sympathetic nervous system. Abnormalities in peripheral vascular reactivity can be demonstrated before the development of overt hypertension. Ordinarily in pregnancy there is a shift in production of

Treatment

Prevention

The history of studies of prophylactic treatments for preeclampsia is an engaging one. Initial small-scale, randomized, controlled trials and meta-analyses of these trials were quite promising. However, large-scale, randomized, controlled trials have suggested either a more limited role for 

Low-dose aspirin was initially suggested to be an ideal preventive treatment for preeclampsia predicated on the current understanding of the pathophysiology of the disease. With regard to 

 

Calcium supplementation for prophylaxis of preeclampsia has a similar history of diminished expectations. Original studies suggested that 2 grams of elemental calcium daily would reduce the incidence of preeclampsia. In 1991, Belizan et al. reported beneficial effects of calcium in 1194 nulliparous women. Calcium was administered beginning the 20th week of pregnancy. Several additional small-scale studies, as well as a meta-analysis combining all studies performed before May 1994, suggested that calcium supplementation reduced the risk of preeclampsia by 62%. Unfortunately, the most recent large-scale trial of calcium supplementation in 4589 nulliparous women reported by Levine et al. revealed no beneficial effects of calcium. Again, these findings seem most secure for women at low risk of developing preeclampsia. It is possible that previous small studies performed at a single center had evaluated women at moderate or high risk for the development of preeclampsia. In the absence of clues as to which women should receive calcium supplementation, calcium cannot be recommended for prophylaxis of preeclampsia at this time.

Management

The time-tested, definitive treatment for preeclampsia is delivery. For women at term, this does not represent a major problem. When preeclampsia occurs between the 32nd and 34th weeks of gestation, obstetricians have some flexibility. Because long-term fetal outcome is likely to be good, delivery still

Hypertension complicating pregnancy represents a risk for both the mother and the fetus, both of whom must be considered when selecting therapy. Hypertension should be treated to prevent maternal morbidity and mortality due to causes such as cerebral hemorrhage. The effect of 

Treatment of mild hypertension (diastolic blood pressure <95 mmHg) usually commences with bed rest. One needs to ascertain that there is no evidence of serious disease such as proteinuria (>500 mg/24 h), renal function impairment (creatinine >1.0 mg/dl), or hyperuricemia. Development of these or 

Methyldopa has been used extensively in pregnancy and is often the agent of first choice. Although this agent has been largely abandoned for general use in essential hypertension because of the

Outcome

Preeclampsia is associated with an increase in perinatal morbidity and mortality. A major feature of preeclampsia is decreased uteroplacental blood flow because of 

Women who develop preeclampsia in a first pregnancy but who are normotensive in subsequent pregnancies have no long-term morbidity or mortality related to the initial episode of