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Complications of Pregnancy

Hypertensive disease complicates 6-8% of all pregnancies in the United States and is one of the major causes of maternal death. Hypertensive disease also significantly increases perinatal morbidity and mortality. Two distinct entities are commonly encountered in pregnant women: chronic hypertension and PIH. These two conditions may coexist; in fact, the risk of developing PIH is significantly increased in women with underlying chronic hypertension. Pregnancy-induced hypertension is a multiorgan disease process that may involve much more than elevated blood pressure. Several clinical subsets are recognized, depending on end-organ effects. Some such subsets have traditionally been given distinct labels, for example, preeclampsia when renal involvement leads to proteinuria, eclampsia when central nervous system involvement leads to seizures, and more recently, HELLP (hemolysis, elevated liver enzymes, and low platelet count) syndrome.

Hypertension is defined as a sustained blood pressure increase to levels of 140 mm Hg systolic or 90 mm Hg diastolic. Blood pressure may depend greatly on patient position; ideally, measurements should be taken in a uniform manner at each prenatal visit; the proper cuff size should be used.

Ordinarily, PIH has its onset after 20 weeks of gestation, and chronic hypertension is defined as hypertension developing before 20 weeks of gestation. Patients with gestational trophoblastic disease are an exception; they can develop classic features of PIH during the first or second trimester.

Patients who develop PIH and, in addition, manifest end-organ involvement or fetal growth restriction are considered to have severe disease. Early delivery should be considered for such women, often despite fetal immaturity. Manifestations that can indicate severe disease are listed in the box.

• Blood pressure >160-180 mm Hg systolic or

>110 mm Hg diastolic

• Proteinuria >5 g/24 h (normal <300 mg/24 h)

• Elevated serum creatinine

• Grand real seizures (eclampsia)

• Pulmonary edema

• Oliguria <500 mL/24 h

• Microangiopathic hemolysis

• Thrombocytopenia

• Hepatocellular dysfunction (elevated alanine aminotransferase, aspartase).

• Intrauterine growth restriction or oligohydramnios

• Symptoms suggesting significant end-organ involvement: headache, visual disturbances, or epigastric or right-upper-

quadrant pain

The etiology of PIH is unknown. However, it is well established that the disease process occurs most often in women who are pregnant for the first time, women with multiple gestation, and women with certain vascular disorders such as those seen with insulin-dependent diabetes, lupus erythematosus, renal disease, and chronic hypertension.

pathophysiologic derangement is vasospasm.

There are several potential maternal consequences of PIH, including cardiovascular and hematologic effects and regional perfusion abnormalities. For example, cardiac output is increased 30-50% in normal pregnant women and is not altered significantly in patients with PIH. The control of peripheral resistance in normal and PIH-complicated pregnancies is critical to understanding blood pressure control because blood pressure is the product of cardiac output times peripheral resistance, and peripheral resistance is increased in women with PIH. This likely occurs as the consequence of an increased sensitivity of the maternal vasculature.

Several studies have addressed the use of low doses of aspirin for the prevention of PIH. A meta-analysis of six con-trolled trials demonstrated a significant reduction in IUGR and cesarean delivery in women judged to be at high risk for PIH based on various criteria. No reduction in perinatal death was seen.

BLEEDING IN THE SECOND HALF OF PREGNANCY

Third-trimester bleeding is a phrase commonly used as a "diagnosis" for bleeding occurring late.

MULTIPLE GESTATION

Multiple gestation occurs in about 1.5% of all births. Although multiple pregnancies of higher order (greater than three) presently constitute a relatively small component of the total, these numbers are increasing as a result of the widespread use of assisted reproductive technologies.

Twins may result either from the splitting of a single fertilized ovum into two genetically identical individuals (monozygotic) or when two separate ova are each fertilized by a sperm.

Management

Antenatal management should include attention to adequate nutrition, avoidance of strenuous physical activity, frequent prenatal visits, and counseling on symptoms of preterm labor, PROM, and hypertensive disorders of pregnancy. Ultrasound assessment of fetal growth and amniotic fluid volume.

Embryo Reduction

The higher-order multiple gestations resulting from assisted reproductive technologies have many associated problems. Of greatest significance to the offspring is the increased risk of preterm delivery.

Despite dramatic progress in the management and prevention of hemolytic disease of the fetus and newborn caused by maternal blood group immunization, it continues to be an important cause of infant morbidity and mortality in the United States. In 1970, the incidence of hemolytic disease in newborns.

Infants born at or below the third percentile of mean weight for gestational age, with clinical evidence of dysfunctional or abnormal growth, are described as growth restricted. The perinatal mortality rate of these infants is five times higher than that of normal infants. Approximately one half of growth-restricted babies show wasting of soft tissue and muscle mass, especially in the cheeks, arms, buttocks, and thighs.

PRETERM LABOR AND DELIVERY

Any birth occurring before the end of 37 weeks of gestation is considered preterm. The incidence is between 8% and 10% of all births, and preterm births account for more than 60% of non-anomalous-related neonatal