Management of blood pressure in pregnancy: new perspectives from the CHAP trial

Chronic hypertension affects up to 10% of pregnancies in the United States and the incidence of hypertensive diseases of pregnancy has more than doubled in the past decade, affecting minority women at disproportionate rates. Recent data show potential benefit by lowering the threshold of blood pressure treatment for pregnant women to >140/90 mmHg.

In April 2022, the results of the Chronic Hypertension and Pregnancy (CHAP) trial was published and demonstrated that lower thresholds (>140/90 vs. >160/110 mmHg) for the initiation of antihypertensive therapy during pregnancy resulted in better pregnancy outcomes without negative impacts to foetal growth. In addition, professional societies, such as the American College of Obstetrics and Gynecology (ACOG) and the Society of Maternal Fetal Medicine (SMFM), have released statements supporting the initiation of antihypertensive therapy at elevations above 140/90 mmHg for pregnant women with chronic hypertension based upon these recent reports.

Treatment of hypertension in pregnant women is controversial, but recent data are emerging that treatment at lower blood pressure thresholds may be associated with improved perinatal outcomes without an increased risk of poor foetal growth. Although these recommendations may be applied to women with chronic hypertension, more research is needed to determine how these guidelines should be applied to other hypertensive diseases of pregnancy.