We have studied 24-h ambulatory blood pressure and kidney function in three groups of adult women: (1) born full term but with birth weights below the 3rd percentile for gestational age (n =18), (2) born preterm before gestational week 33 (median birth weight 1,250 g, range 950-2,040 g) (ex-preterm, n =14), and (3) those born full term with normal birth weights (comparison group n =17). We have previously published the results from the study. We recalculated the daily ambulatory blood pressure and redefined the time interval from 6:00-24:00 to 8:00-20:00, since this better corresponds to daily active life. We found significantly increased mean daily systolic ambulatory blood pressure in the ex-preterm group. The result supports the suggestion that disturbance and/or disruption of the normal prenatal milieu seem to affect arterial blood pressure in adult life.