Severe hypertension in pregnancy is a hypertensive crisis that requires urgent and intensive care due to its high maternal and fetal mortality. However, there still remain some discrepancies between guidelines in a target blood pressure to prevent severe hypertension in pregnancy. This study aimed to find the optimal blood pressure (BP) levels to prevent severe hypertension in pregnant women with nonsevere hypertension.
Design and method:
We searched Ovid MEDLINE and the Cochrane Library to identify all randomized controlled trials, which compared effects of antihypertensive drugs and placebo/no treatment or more intensive and less intensive BP-lowering treatments on adverse maternal and fetal pregnancy outcomes among pregnant women with nonsevere hypertension. A random effects model meta-analysis was performed to estimate the pooled risk ratio (RR) and 95% confidence interval (CI) for the outcomes.
Forty RCTs with 6355 patients were included in this study. BP lowering treatment significantly prevented severe hypertension (RR, 0.46; 95% CI, 0.37 to 0.56), preeclampsia (RR, 0.82; 95% CI, 0.69 to 0.98), severe preeclampsia (RR, 0.38; 95% CI, 0.17 to 0.84), placental abruption (RR, 0.52; 95% CI, 0.32 to 0.86), and preterm birth (before 37 weeks; RR, 0.81; 95% CI, 0.71 to 0.93), while the risk of small for gestational age infants was increased (RR, 1.25; 95% CI, 1.02 to 1.54). An achieved systolic blood pressure (SBP) of lower than 130 mmHg reduced the risk of severe hypertension to nearly one-third compared with an achieved SBP of 140 mmHg or higher, with a significant interaction of the BP levels achieved with BP lowering therapy. There was no significant interaction between BP lowering treatment and the subtypes of hypertensive disorders of pregnancy, including gestational hypertension, preeclampsia, and chronic hypertension.
BP lowering treatment aimed at a SBP of lower than 130 mmHg and accompanied by careful monitoring of fetal growth might be recommended to prevent severe hypertension among pregnant women with nonsevere hypertension.