Even mild chronic hypertension during pregnancy triples the risk of perinatal death, doubles the risk for placental abruption, and increases the risk of impaired fetal growth and death, according to a review of scientific evidence on the subject. There is consensus that intensive monitoring and antihypertensive treatment are warranted for pregnant women with severe hypertension (blood pressure of 160/110 mm Hg or higher), but uncertainty exists about management of those who have mild chronic hypertension.
Antihypertensive agents are used in pregnancies complicated by mild chronic hypertension despite unclear tradeoffs between potential benefits and harms. Even the use of aspirin is controversial, says Cynthia D. Mulrow, M.D., M.Sc., of the San Antonio Evidence-based Practice Center (EPC) at the University of Texas Health Sciences Center. The EPC is supported by the Agency for Healthcare Research and Quality (contract 290-97-0012).
Dr. Mulrow and colleagues reviewed 215 articles on management of mild chronic hypertension during pregnancy. They found that no one agent significantly reduced perinatal mortality. However, there was clear evidence that angiotensin-converting enzyme inhibitors were harmful to second- and third-trimester fetuses and are best avoided. Evidence on the risks for fetal growth impairment with beta-blockers and alpha/beta blockers was conflicting. The best evidence suggested that atenolol given early in pregnancy was associated with fetal growth retardation.
Trials showed that aspirin neither reduced nor increased perinatal and maternal morbidity, but they did not rule out possible small-to-moderate beneficial or adverse effects. No studies provided guidance on the benefits or consequences of various nonpharmacologic therapies or monitoring strategies, such as serial ultrasonography to measure fetal growth, nonstress testing, biophysical profiles, and doppler flow velocity measurements that are designed to detect the complications of chronic hypertension.
See "Management of mild chronic hypertension during pregnancy: A review," by Robert L. Ferrer, M.D., M.P.H., Baha M. Sibai, M.D., Dr. Mulrow, and others in the November 2000 Obstetrics & Gynecology 96(5), pp. 849-860.
Editor's Note: This journal article is based on Evidence Report/Technology Assessment No. 14, Management of Chronic Hypertension During Pregnancy, prepared for AHRQ by the San Antonio EPC. A summary of the report (AHRQ Publication No. 00-E010) and the full report (AHRQ Publication No. 00-E011) are available from the AHRQ Publications Clearinghouse.
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