Pregnancy-Induced Hypertension (PIH)

Toxemia of pregnancy, or pregnancy induced hypertension (PIH), usually develops late in the second trimester or in the third trimester. Preeclampsia, the nonconvulsive form of toxemia, develops in about 7% of pregnancies. It may be mild or severe, and the incidence is significantly higher in low socioeconomic groups.

Eclampsia is the convulsive form of toxemia. About 5% of women with preeclampsia develop eclampsia; of these, about 15% die of toxemia itself or its complications. Fetal mortality is high because of the increased incidence of premature delivery.

Causes

The cause of PIH is unknown, but it appears to be related to inadequate prenatal care (especially poor nutrition), parity (more prevalent in primigravidas), multiple pregnancies, preexisting diabetes mellitus, and hypertension.

Age is also a factor. Adolescents and primaparas over age 35 are at higher risk for preeclampsia. Other theories postulate a long list of potential toxic sources, such as autolysis of placental infarcts, autointoxication, uremia, maternal sensitization to total proteins, and pyelonephritis.

Signs and symptoms

Rapid or sudden weight gain, high blood pressure, protein in the urine, and swelling (in the hands, feet, and face) are all signs of PIH. Some swelling is normal during pregnancy. However, if the swelling doesn't go away and is accompanied by some of the above symptoms, be sure to see your doctor right away. Other symptoms of PIH include abdominal pain, severe headaches, a change in reflexes, reduced output of urine or no urine, blood in the urine, dizziness, or excessive vomiting and nausea.

Diagnosis

The diagnosis is made by comparing blood pressures taken of the mother at the prenatal visits. Once a certain threshold level is attained, or a significant elevation of the blood pressure from baseline has occurred, then pregnancy induced hypertension is present.

Treatment

Adequate nutrition, good prenatal care, and control of preexisting hypertension with hydralazine (Apresoline) during pregnancy decrease the incidence and severity of preeclampsia. Early recognition and prompt treatment of preeclampsia can prevent progression to eclampsia. Therapy for preeclampsia is designed to halt the disorder's progress - specifically, the early effects of eclampsia, such as seizures, residual hypertension, and renal shutdown - and to ensure fetal survival. Some doctors advocate the prompt induction of labor, especially if the patient is near term; others follow a more conservative approach.

Conservative measures

Therapy may include sedatives such as phenobarbital along with complete bed rest to relieve anxiety, reduce hypertension, and evaluate response to therapy. If renal function remains adequate, a high-protein, low-sodium, low-carbohydrate diet with increased fluid intake is recommended.

If blood pressure fails to respond to bed rest and sedation and persistently rises above 160/100 mm Hg or if CNS irritability increases, magnesium sulfate may produce general sedation, promote diuresis, reduce blood pressure, and prevent seizures.

Cesarean section

If these measures fail to improve the patient's condition or if fetal life is endangered (as determined by stress or noustress tests), cesarean section or oxytocin induction may be required to terminate the pregnancy.

Treatment for seizures

Emergency treatment of eclamptic seizures consists of immediate administration of I.V diazepam, followed by magnesium sulfate (I. Y. drip), oxygen administration, and electronic fetal monitoring. After the patient's condition stabilizes, a cesarean section may be performed.

Prevention

Early identification of women at risk for pregnancy-induced hypertension may help prevent some complications of the disease. Education about the warning symptoms is also important because early recognition may help women receive treatment and prevent worsening of the disease.