Update on the Use of Antihypertensive Drugs in Pregnancy

Abstract

S the most common medical disorder of pregnancy, hyper- tension is reported to complicate 1 in 10 pregnancies1,2 and affects an estimated 240 000 women in the United States each year.3 Antihypertensive treatment rationale in this group repre- sents a departure from the nonpregnant adult Seventh Report of the Joint National Committee on Prevention, Detection, Evalu- ation, and Treatment of High Blood Pressure guidelines.4 First, during pregnancy, the priority regarding hypertension is in making the correct diagnosis, with the emphasis on distinguish- ing preexisting (chronic) from pregnancy induced (gestational hypertension and the syndrome of preeclampsia). Second, much of the obstetric literature distinguishes blood pressure (BP) levels as either mild (140 to 159/90 to 109 mm Hg) or severe (160/110 mm Hg), rather than as stages (as in Seventh Report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure; Table 1). Third, in contrast to hypertension guidelines in adults, which emphasize the importance of systolic BP, much of the obstetric literature focuses on diastolic rather than systolic BP, in part because of the lack of clinical trials to support one approach versus another. The focus of treatment is the 9 months of pregnancy, during which untreated mild-to-moderate hyperten- sion is unlikely to lead to unfavorable long-term maternal outcomes. In this setting, antihypertensive agents are mainly used to prevent and treat severe hypertension; to prolong pregnancy for as long as safely possible, thereby maximizing the gestational age of the infant; and to minimize fetal exposure to medications that may have adverse effects. During pregnancy, the challenge is in deciding when to use antihypertensive medications and what level of BP to target. The choice of antihypertensive agents is less complex, because only a small proportion of currently available drugs have been adequately evaluated in pregnant women, and many others are contraindi- cated. Appropriate use of antihypertensive drugs in specific pregnancy-associated hypertensive disorders, including thera- peutic BP goals and criteria for selecting specific antihyperten- sive drugs, are discussed in this review.