Prediction of later hypertension following a hypertensive pregnancy.

The aim of the present study was to identify factors predicting later hypertension following a hypertensive pregnancy. In the years 1969-1973, 261 out of a total of 17 000 pregnancies were complicated by pre-eclampsia or hypertension in pregnancy. In a follow-up study seven to 12 years later, 238 (91.2%) of these women were investigated. It was discovered that 26.4% of the women had hypertension and 10.1% had borderline hypertension compared with 2 and 6.5% respectively in a group of matched control subjects. A stepwise regression analysis was performed in order to evaluate the association between nine different variables and blood pressure at follow-up. We found that systolic blood pressure in early pregnancy was the single most important factor predicting systolic blood pressure at follow-up (r2 = 0.28). When highest recorded blood pressure before delivery and age were entered into the statistical model, r2 was increased to 0.35 (P less than 0.0001). Unlike previous studies, parity and proteinuria did not add to the predictive power of the analysis. Late hypertension was found in more than 25% of women seven to 12 years after a hypertensive pregnancy. The most important factor associated with later hypertension was blood pressure before pregnancy.