Hypertension during pregnancy

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Chapter 19 HYPERTENSION DURING PREGNANCY

Hypertension is defined as systolic blood pressure of 140 or higher, a diastolic blood pressure of 90 or higher, or both. Women with hypertension during pregnancy need to be monitored carefully because of the significant risk of morbidity and mortality in the mother, fetus, and newborn. Hypertension during pregnancy is classified as gestational hypertension, preeclampsia, eclampsia, or chronic hypertension.

Gestational hypertension is hypertension that develops after 20 weeks of pregnancy and resolves by 12 weeks post partum. About 25% of women with gestational hypertension develop preeclampsia. Preeclampsia is gestational hypertension that is associated with proteinuria (≥0.3 g of protein/24 hours). Eclampsia is the presence of seizures in a pregnant woman with preeclampsia.

Risk factors for preeclampsia include first pregnancy, multiple fetuses, chronic hypertension, diabetes, renal disease, thrombophilia, vascular and connective tissue disease, obesity, maternal age of greater than 35 years, or maternal age of less than 20 years.

Chronic hypertension is hypertension that starts before the 20th week of pregnancy. Patients with chronic hypertension are at considerable risk of developing superimposed preeclampsia. Possible complications of chronic hypertension include preterm labor, intrauterine growth restriction, fetal death, and placental abruption.

Key Historical Features

✓ Obstetric history

• Gravity and parity

• Previous obstetric complications, including hypertension, diabetes, fetal loss, preterm labor

• Gestational age or most recent menstrual period

• Fetal movement

• Contractions

• Vaginal bleeding

• Rupture of membranes

✓ Medical history, especially history of the following:

• Diabetes mellitus

• Hypertension

• Vascular and connective tissue disease

• Kidney disease

• Thrombophilia

• Thyroid disease

✓ Medications

✓ Social history

• Tobacco, alcohol, or illicit drug use

✓ Family history, especially history of hypertension, kidney disease, or diabetes

✓ Neurologic symptoms

• Headaches and visual disturbances, which are associated with severe preeclampsia

✓ Gastrointestinal symptoms

• Epigastric and/or right upper quadrant pain, both of which are associated with severe preeclampsia

• Oliguria, which may be associated with severe preeclampsia

Key Physical Findings

✓ Vital signs

• Blood pressure should be measured with the patient either sitting up or in the left lateral recumbent position; the patient’s arm should be at the level of the heart; patients should be seated for at least 5 minutes before the measurement, and at least two measurements should be made; and an appropriate size cuff should be used (cuff bladder encircles at least 80% of the arm)

✓ General evaluation for rapid weight gain or facial edema, because fluid retention is associated with preeclampsia

✓ Funduscopic examination for evidence of retinopathy in patients with chronic hypertension

✓ Cardiovascular examination for arrhythmias, heart murmurs, abnormal heart sounds, carotid or femoral bruits, and peripheral pulses

✓ Pulmonary examination for evidence of pulmonary edema

✓ Obstetric evaluation to determine fundal height for fetal growth

✓ Gastrointestinal examination for right upper quadrant tenderness, liver enlargement, or an enlarged kidney

Suggested Work-Up

Urinalysis	To evaluate for proteinuria and glucosuria
Twenty-four-hour urine sampling for total protein or spot urine protein/creatinine ratio	To evaluate for and quantify proteinuria
Complete blood cell count	Because hemoconcentration occurs with preeclampsia and because hemolysis and thrombocytopenia may be associated with preeclampsia as part of the syndrome of hemolysis, elevated liver enzyme counts, and low platelet count (HELLP)
Serum creatinine measurement	Elevated creatinine levels may be associated with chronic kidney disease or preeclampsia

In women who develop hypertension after 20 weeks, the following testing should be performed in addition to the tests just described:

Uric acid measurement	Elevated uric acid level is associated with preeclampsia
Lactate dehydrogenase (LDH) measurement	Elevated LDH level may be a sign of hemolysis
Partial thromboplastin time (PTT), prothrombin time (PT), and international normalized ratio (INR) measurements	To evaluate for coagulopathy
Alanine transaminase (ALT) and aspartate transaminase (AST) measurements	Elevated liver enzyme levels are suggestive of severe preeclampsia

Additional Work-Up

Obstetric ultrasonography	Baseline ultrasonography should be performed at 18 to 20 weeks of pregnancy
	According to the Working Group on High Blood Pressure in Pregnancy, ultrasonography for fetal growth and amniotic fluid should be repeated every 3 weeks in patients with mild preeclampsia if the sonograms are normal
	In patients with chronic hypertension, ultrasonography should be repeated only if there is a change in maternal or fetal condition or if fetal growth cannot be assessed through fundal height measurement (e.g., with maternal obesity)
Nonstress test and biophysical profile	Both should be performed regularly to evaluate fetal well-being
Electrocardiography	To evaluate for evidence of left ventricular hypertrophy in patients with chronic hypertension
Echocardiography	May be considered in patients with chronic hypertension to evaluate for left ventricular hypertrophy

FURTHER READING

ACOG Committee on Practice Bulletins. ACOG Practice Bulletin. Chronic hypertension in pregnancy. ACOG Committee on Practice Bulletins. Obstet Gynecol. 2001;98(1Suppl):177-185.

ACOG Committee on Practice Bulletins–Obstetrics. ACOG practice bulletin. Diagnosis and management of preeclampsia and eclampsia. Number 33, January 2002. Obstet Gynecol. 2002;99:159-167.

Beckmann CRB, Ling FW, Smith RP, et al. Hypertension in Pregnacy. In Obstetrics and Gynecology, 5th, Philadelphia: Lippincott Williams & Wilkins; 2006:188-196.

Report of the National High Blood Pressure Education Program Working Group on High Blood Pressure in Pregnancy. Am J Obstet Gynecol. 2000;183(1):S1-S22.

The Seventh Report of the Joint National Committee on the Prevention, Detection, Evaluation and Treatment of High Blood Pressure. Washington, DC: U.S. Department of Human and Health Services, December 2003

Wagner LK. Diagnosis and management of preeclampsia. Am Fam Physician. 2004;70:2317-2324.

Zamorski MA, Green LA. NHBPEP report on high blood pressure in pregnancy: a summary for family physicians. Am Fam Physician. 2001;64:263-270.

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