Authors' objectives:

The purpose of this report is to help clinicians make informed choices about therapeutic interventions for pregnant women with chronic hypertension and to aid organizations developing guidelines for the treatment of this condition. The report evaluates evidence regarding risks of chronic hypertension, benefits and adverse effects of pharmacotherapy (antihypertensives and aspirin), nonpharmacological treatment, and monitoring techniques.

Authors' recommendations: Benefits of treating chronic hypertension before conception: There was no evidence that addressed the effect of blood pressure control before conception on fetal outcomes. With regard to maternal outcomes, evidence from randomized trials involving nonpregnant women 30 to 54 years of age showed that approximately 250 (95 percent confidence interval 158 to 1,606) such women with mild to moderate hypertension need to be treated for 5 years to prevent one cardiovascular event such as stroke or myocardial infarction. Much larger numbers of women younger than age 30 (approximately 8,000) would need to be treated for 1 year to prevent a cardiovascular event. Benefit of treating chronic hypertension during pregnancy: There was insufficient evidence to prove or disprove moderate to large clinical effects of antihypertensive agents on perinatal outcomes. Adverse effects of antihypertensive drugs: The quality of evidence addressing this question was poor. The best-established adverse effect of antihypertensive agents in pregnancy was renal failure associated with use of the angiotensin-converting enzyme inhibitors. There was evidence suggesting that atenolol used early in pregnancy may be associated with small-for-gestational-age fetuses. Effects of nonpharmacological interventions: There was no evidence to address this question. Optimum levels for initiating therapy and risk of chronic hypertension in pregnancy: There was insufficient evidence to identify an optimum blood pressure at which treatment should be initiated and thereafter maintained. Chronic hypertension in pregnancy tripled the risk of perinatal mortality and doubled the risk of placental abruption. The risks of preeclampsia and small-for-gestational-age infants also were increased. Increased risk was evident even in the absence of superimposed preeclampsia. Effect of aspirin: A single trial showed low-dose aspirin begun before 26 weeks gestational age neither reduced perinatal morbidity and mortality nor increased maternal risks in women with chronic hypertension. Although the trial was of moderate size, small increases or reductions in benefits or risks could have been missed. Effectiveness of monitoring strategies: There was insufficient evidence to evaluate the effectiveness of any particular monitoring test or sequence of tests for women with chronic hypertension in pregnancy.

Authors' methods: Systematic review

Project Status: Completed

URL for project: http://www.ahrq.gov/clinic/pregsum.htm

Year Published: 2000

English language abstract: An English language summary is available

Publication Type: Not Assigned

Country: United States

Organisation Name: Agency for Healthcare Research and Quality

Contact Address: Center for Outcomes and Evidence Technology Assessment Program, 540 Gaither Road, Rockville, MD 20850, USA. Tel: +1 301 427 1610; Fax: +1 301 427 1639;

Contact Name: martin.erlichman@ahrq.hhs.gov

Contact Email: martin.erlichman@ahrq.hhs.gov

Copyright: Agency for Healthcare Research and Quality (AHRQ)