The aim of this study was to reveal correlation between Doppler in the fetal middle cerebral artery and fetal decompensation during labor in uncomplicated pregnancies at 40 weeks and beyond. We by means of ultrasound Doppler examined 260 women at 40 to 42 weeks of uncomplicated pregnancy 48 hours before delivery, with fetal condition as sessed subsequently during labor and immediately after delivery. We found out that in the group of women with caesarean section caused by fetal distress during labor, pulsatility indices in the middle cerebral artery evaluated just before labor were significantly lower than in the group of women whose fetus had better condition during labor. The same trend was observed when comparing Doppler velocimetry using the fetal cerebroplacental ratio. Moreover, we identified that in the group of women with newborns having Apgar 7 and less, middle cerebral artery measured less than 48 hours before delivery were lower than in the group of women having babies in better conditions. Furthermore, as result of this study, the trigger threshold for PI was found to be 0.835, below which fetuses have adverse perinatal outcome during labor. Thus, it was shown that Doppler in the fetal middle cerebral artery in uncomplicated pregnancies at 40 weeks and beyond could predict fetal distress and avoid hypoxic brain damage to the fetus during labor.