Antihypertensive therapy in pregnancy

A 35-year-old woman who is 15 weeks pregnant is referred for evaluation of chronic hypertension. She discontinued her antihypertensive regimen when she learned that she was pregnant.

On physical examination, heart rate is 90/min and blood pressure is 160/98 mm Hg. Cardiac and pulmonary examinations are normal.

Laboratory Studies
Blood urea nitrogen 6 mg/dL
Creatinine 0.6 mg/dL
Sodium 136 meq/L
Potassium 3.7 meq/L
Bicarbonate 23 meq/L

Treatment with which of the following agents is most appropriate for this patient?
A Hydrochlorothiazide
B Labetalol
C Lisinopril
D Losartan

Answer and Critique (Correct Answer = B)


Key Point
Labetalol or methyldopa is the preferred treatment for chronic hypertension in pregnant patients.

The most appropriate treatment for this patient is labetalol therapy. This agent has been used extensively in pregnancy because of its combined α-and β-blocking properties. Methyldopa also has been used extensively in pregnancy and is one of the only agents in which long-term follow-up of infants exposed in utero has proved to be safe.

Diuretic agents may interfere with the normal physiologic volume expansion associated with pregnancy. Therefore, initiation of diuretic therapy during pregnancy usually is not recommended in the absence of renal insufficiency. However, if needed, patients with hypertension treated with chronic diuretic therapy before conception may continue treatment with these agents at lower doses. Angiotensin-converting enzyme inhibitors and angiotensin receptor blockers are contraindicated in pregnancy because of adverse effects on fetal renal function, particularly after second- and third- trimester exposure. There is no clear association between these drugs and teratogenic effects after first-trimester exposure. However, avoidance of these drugs is indicated during all trimesters of pregnancy because of the risk for negative fetal outcomes.