Management of the pregnant patient with chronic hypertension.

Once the diagnosis of chronic hypertension in pregnancy has been made, many centers in the United States treat moderate to severe cases of chronic hypertension pharmacologically, hoping to delay or obviate the onset of superimposed preeclampsia and to improve perinatal outcome. Methyldopa, which is most often used, is the only antihypertensive drug for which there is no evidence of adverse effects in long-term follow-up studies of fetuses exposed to it. Newer beta-blocker drugs such as atenolol and labetalol are receiving much attention abroad. These newer drugs have fewer maternal side effects and, as yet, no adverse effects on fetuses have been seen. Clinical trials of labetalol will soon start in the United States.