Management of mild chronic hypertension during pregnancy: A review

Objective: To conduct a systematic review of evidence relating to managemen t of mild chronic hypertension during pregnancy, including associated risks , benefits, and harms of treatment with antihypertensive agents, nonpharmac ologic measures, and aspirin and benefits of various monitoring strategies. Data Sources: Using four broad search strategies, we searched English and n on-English-language citations in 16 electronic databases from their incepti on to February 1999 and consulted relevant textbooks, references, and exper ts. Study Selection: Reviewers screened 6228 abstracts and found 215 articles t hat met multiple prespecified patient selection, study population, and desi gn criteria. Tabulation, Integration, and Results: Forty-six studies consistently showed that chronic hypertension triples the risk for perinatal mortality (odds r atio [OR] 3.4; 95% confidence interval [CI] 3.0, 3.7) and doubles the risk for placental abruption (OR 2.1; 95% CI 1.1, 3.9). Thirteen small, randomiz ed controlled trials had inadequate power to rule in or rule out moderate-t o-large (20%-50%) benefits of antihypertensive treatment. Possible adverse effects were fetal renal failure when angiotensin-converting enzyme inhibit ors are used in the second or third trimester and growth restriction when a tenolol is used early in pregnancy. Trials showed that aspirin neither redu ces nor increases perinatal and maternal morbidity, but they did not rule o ut possible small-to moderate beneficial or adverse effects. No studies pro vide guidance on benefits or consequences of various nonpharmacologic thera pies or monitoring strategies. Conclusion: Mild chronic hypertension is associated with increased maternal and fetal risks. Beneficial treatment and monitoring regimens are not clea r, but some treatments, such as angiotensin-converting enzyme inhibitors, a re best avoided. (Obstet Gynecol 2000;96:849-60. (C) 2000 by The American C ollege of Obstetricians and Gynecologists.).