Ten term pregnancy placentas from preeclampsic cases, uncomplicated by essential hypertension, IUGR or renal disease were studied by means of histomorphometric analysis and the results were compared with 10 term pregnancy normal placentas. There was no significant statistical difference in the parameters between the two groups. In the membrane rolls and in a portion of placental bed biopsies from preeclampsic patients there was no acute atherosis in the spiral arteries. This study demonstrated that, the morphological and functional changes in the placentas of preeclampsia yielded little effect on fetal growth and that acute atherosis in spiral artery was not pathognomonic of preeclampsia.