Usefulness of ambulatory blood pressure monitoring in pregnant women with type 1 diabetes

OBJECTIVE - Pregnancy in type 1 diabetes is associated with an increased ri sk of developing pregnancy-induced hypertension (PIH). Ambulatory blood pre ssure monitoring (ABPM) has been used to screen for preeclampsia in nondiab etic pregnancy. To date, there are no data regarding ABPM during pregnancy in normotensive type 1 diabetic women. This study sought to establish blood pressure (BP) profiles for pregnant type 1 diabetic women using ABPM and d etermine whether the BP pattern can define a population at risk for develop ing PIH. RESEARCH DESIGN AND METHODS - ABPM was carried out for one 24-h period duri ng each trimester-in the first trimester between weeks 7 and 12, in the sec ond trimester between weeks 20 and 24, and in the third trimester between w eeks 30 and 34-in 22 normotensive pregnant type 1 diabetic and 10 pregnant nondiabetic women. RESULTS - The incidence of PIH was fourfold greater in type 1 diabetic wome n than in control subjects. Diabetic women showed higher daily diastolic BP in the third trimester compared with nondiabetic pregnant women. Diabetic women who developed PIH in the third trimester showed significantly higher BP profiles throughout gestation than those who remained normotensive. Rece iver operator characteristics curves for nighttime systolic BP showed the b est predictive capacity for PIH, with a cutoff >105 mmHg (85% sensitivity a nd 92% specificity). CONCLUSIONS - Our study confirms the early increase of BP in patients who w ill develop PIH and suggests that nighttime systolic BP >105 mmHg in the se cond trimester is a useful predictor of PIH. ABPM may be useful in screenin g for PIH in pregnant diabetic women.