Monitoring and evaluation of out-of-office blood pressure during pregnancy.

Blood pressure (BP) is important to measure during pregnancy because it provides the basis for classifying hypertension, which has several etiologies. Similarly, monitoring home and ambulatory BP can provide useful information outside a medical setting for adults who are not pregnant. Office BP is higher during early pregnancy in primiparous women than in multiparous women, whereas out-of-office BP does not differ between them. White-coat hypertension might be benign compared with hypertension determined from ambulatory BP values that might be associated with a high risk for preeclampsia. Although reference values have been proposed on the basis of the distribution of BP among normotensive pregnant women, prognosis-based reference values are also required.