The CHAP trial shows that target BP in pregnant women with mild chronic hypertension should be less than 140/90 mmHg to improve maternal and foetal/neonatal outcomes. However, the lower safety margin, i.e. a BP level that is too low and potentially hazardous, remains still unclear.
The findings of the CHAP trial should be extrapolated with caution to women of Asian ancestry. Studies on the long-term effects of antihypertensive drug treatment in women with mild chronic hypertension and their offspring are lacking.
Whether pregnancy-validated automated devices may replace the traditional auscultatory BP measurements should be examined in future trials. Secondary analyses of the CHAP data comparing outcomes based on standardised pragmatic clinic BP vs. standardised automated clinic BP are awaited.