What is the cut-off BP value for pregnant women at risk of masked hypertension?
Having identified the prevalence and increased risk of masked hypertension in pregnant women, a recent study suggests that an office blood pressure (BP) of at least 125/75 mm Hg in the second half of gestation may be appropriate to indicate out-of-office measurements in high-risk pregnancies.
Of the 373 women (mean age, 30±7 years with 32±4 weeks of gestation), 69 (18.5 percent) developed pre-eclampsia or eclampsia. A stepwise increase was seen in the risk for pre-eclampsia or eclampsia through quartiles of systolic office BP (8.8 percent, 13.4 percent, 19.6 percent and 32.3 percent; p<0.001) and diastolic office BP (6.5 percent, 13.7 percent, 19.6 percent and 34.4 percent; p<0.001).
There was a significant increase in odds ratio (OR) through quartiles of systolic (p=0.004) and diastolic (p<0.001) office BP. The significance manifested more between the second and third quartile, with the cut-off point being 125/76 mm Hg.
The prevalence of white-coat hypertension was 3.8 percent and masked hypertension 24.7 percent. Using ambulatory BP monitoring (ABPM), 14 of 61 office hypertensive women were reclassified as having white-coat hypertension and 92 of 312 normotensive women as having masked hypertension.
Furthermore, there was a significant increase in OR for pre-eclampsia or eclampsia in women with masked hypertension.
Absolute risk for pre-eclampsia or eclampsia was comparable between women with office BP <125/75 mm Hg and those with normal ABPM (7.2 percent vs 7.1 percent).
This prospective cohort study included women in the second half of high-risk pregnancies. Participants had their office and ambulatory BP measured, and were divided according to quartiles of office BP and in normotension, white-coat hypertension, masked hypertension and sustained hypertension. The investigators then estimated the risks for pre-eclampsia or eclampsia for each category.