CHAPTER 7 PREGNANCY AT RISK
SECTION 1: HYPERTENSIVE STATES OF PREGNANCY
1. Classification and Clinical Features
2. Diagnosis
2.1 Clinical Findings
2.1.1 Symptoms and Signs
（1）Hypertension
Hypertension is the most important criterion for the diagnosis of preeclampsia, and it may occur suddenly.
（2）Proteinuria
Proteinuria is the last sign to develop. Eclampsia may occur without proteinuria. One set of researchers found no proteinuria in 29% of one series of eclamptic patients. Most patients with proteinuria will have glomeruloendotheliosis on kidney biopsy. Proteinuria in preeclampsia is an indicator of fetal jeopardy.
（3）Edema
Previousy a weight gain of more than 2 Ib/wk or a sudden weight gain over 1 to 2 days was considered worrisome.
（4）Differing clinical picture in preeclamptic crises
Preelampsia-eclampsia is a multisystem disease with varying clinical presentations. One patient may present with eclamptic seizures, another with liver dysfunction and intrauterine growth retardation, another with pulmonary edema, still another with abruption placentae and renal failure, and another with ascites and anasarca.
2.2 Laboratory Findings
The hemoglobin and hematocrit may be elevated due to hemoconcentration, or in more severe cases, there may be anemia secondary to hemolysis. Thrombocytopenia is often present. Fibrin split products and decreased coagulation factors may be detected. Uric acid is usually elevated above 6 mg/dL. Serum creatinine is most often normal （0.6-0.8mg/dl）but may be elevated in severe preeclampsia. Although hepatic abnormalities occur in about 10% of patients, the bilirubin is usually below 5 mg/dl and the aspartate aminotransferase （AST）below 500U. Alkaline phosphatase may increase 2- to 3- fold. Lactate dehydrogenase may be quite high. Blood glucose and electrolytes are normal. Urinalysis reveals proteinuria and occasional hyaline casts.
3. Differential Diagnosis
The differential diagnosis of hypertensive states of pregnancy includes chronic nephritis of pregnancy. The differential diagnosis of eclampsia includes epilepsy, encephalitis, cerebral tumor, vascular malformations rupture hemorrhage, hyperosmolar nonketotic diabetic coma, hypoglycemic coma.
4. Treatment
4.1 Mild Preeclampsia
4.1.1 Treatment of mother
The treatment of preeclampsia is bed rest and delivery. Women with mild preeclampsia who can be relied on to follow the physician's instructions may be treated as outpatients. A typical home regimen consists of bed rest, daily urine dipstick measurements of proteinuria, and blood pressure monitoring. Patients are seen at least twice weekly for antepartum fetal heart rate testing and periodic 24-hour urine protein measurements. Patients must be warned of danger signals such as severe headache, epigastric pain, or visual disturbances. The occurrence of these signals, increasing blood pressure, or proteinuria mandates communication with the physician and probable hospitalization.
4.1.2 Assessment of fetal status
Fetal status is evaluated by twice-weekly nonstress tests and ultrasound assessment of amniotic fluid volume. Nonre-active nonstress tests require further evaluation with either a biophysical profile or an oxytocin chanllenge test. Amniocentesis to determine the lecithin: sphingomyelin （L:S）ratio is not frequently used in preeclampsia, since early delivery is usually for maternal indications, but it may be useful as the fetus approaches maturity. Corticosteroids should be used to accelerate fetal lung maturity in patients with preeclampsia when the delivery may occur in the next 2-7days.
4.2 Severe preeclampsia
The goals of management of severe preeclampsia are:
（1）prevention of convulsions;
（2）control of maternal blood pressure;
（3）Initiation of delivery. Delivery is the definitive mode of therapy. If severe preeclampsia develops at or beyond 36 weeks' gestation or if there is evidence of fetal lung maturity or fetal jeopardy delivery has little risk for the fetus. If delivery of a preterm infant （＜ 36 weeks' gestation）is anticipated, maternal transfer to a tertiary care center is advised to ensure proper neonatal intensive care.
All women at 40 weeks with mild preeclampsia should be delivered. At 38 weeks, women with mild preeclampsia and a favorable cervix should be induced. Anyone at 32-34 weeks with severe preeclampsia should be considered for delivery, and the fetus may benefit from corticosteroids. In patients 23-32 weeks with severe preeclampsia, delivery may be delayed in an effort to reduce perinatal morbidity and mortality. This should be done only at a tertiary care center. The mother should be placed on magnesium sulfate for a minimum of the first 24 hours while the diagnosis is made. Blood pressure should be controlled with the medications.The patient should be given corticosteroids to promote fetal lung maturity. The mother may be closely observed with frequent laboratory evaluations. Indications for delivery include development of symptoms, laboratory evidence of organ damage, and fetal deterioration. If the gestational age is less than 23 weeks, the patient should be offered induction of labor to terminate the pregnancy.
Vaginal delivery is preferable to cesarean section and labor induction should be aggressive. A clear endpoint for delivery should be determined, usually within 24 hours. If delivery is not achieved within the set time frame, cesarean is warranted.
4.3 Eclampsia
4.3.1 Prenatal treatment
（1）Control of seizures
（2）Control of hypertension: hydralazine, labetalol, nifedipine, sodium nitroprusside, nitroglycerin
4.3.2 Postpartum treatment
Some of the constraints of therapy no longer apply once delivery has occurred. Since 25% of eclamptic seizures occur postpartum, patients with preeclampsia are maintained on magnesium sulfate for 24 hours after delivery. Hypertension may not resolve until 6 weeks postpartum, and number of antihypertensive agents could be given, including a diuretic, calcium channel blocker, ACE inhibitor, central alpha agonist, or beta-blocker. The blood pressure should be checked in the standing position to avoid the possibility of orthostatic hypotension. At follow-up after 1 week, the need for continuing antihypertensive therapy may be reevaluated.
（王皓）