In normal human gestations during the first and the second trimester, the uterine spiral arteries are converted into utero-placental arteries (high capacity/low resistance vessels) through a replacement of the muscolo-elastic components of the arterial walls. The physiological changes in the spiral arteries are revealed in an increase of the end diastolic component of the uterine blood flow. This can be easily detected by Doppler velocimetry of the uterine arteries and its branches (Ferrazzi et al., 1999).Ischemic changes occur more frequently in the placentas from women whose pregnancy is complicated with preeclampsia (PET) or intrauterine growth restriction (IUGR) than in those with other complications of pregnancy (Hofstatter et al., 1996).It has long been assumed that in insufficient uterine, placental and fetal circulations result in adverse pregnancy outcome and these abnormalities can be defined with the use of Doppler ultra sonography. Indeed, observational studies have clearly established an association between abnormal velocity waveforms and adverse perinatal outcome such as intrauterine growth restriction, foetal asphyxia and perinatal mortality (North et al., 1999).This study was done on 150 primigravida, sure of dates, in the third trimester with singleton pregnancy attending ante-natal clinic and delivery ward at Obstetrics and Gynecology departments and Pathology departments at Zagazig University Hospitals. They were divided into three groups, 50 cases each.(1) The control group ( Normal pregnancy):Healthy pregnant women without medical or obstetric complications and all laboratory investigations were normal.(II) Patients with severe pre-eclampsia:(III) Patients with Intra-uterine growth restriction:This group included pregnancies complicated with IUGR, but without any symptoms of pre-eclampsia or pre-existing hypertension.All patients were subjected to:I- History, general and obstetric examinations.II- Routine laboratory investigations.III- Ultrasonographic and Doppler studies included uterine artery Doppler velocimetry.IV- Histopathology of the placenta.All cases were evaluated for the assessment of:* Maternal complications.* Mode of delivery.* Perinatal outcome.The correlation between uterine artery Doppler indices and histopathologic changes of placentas was studied and the data obtained were collected, tabulated and statistically analyzed.The results of the present study showed:I- Uterine artery Doppler indices were significantly higher in PET and IUGR groups than control group.II- As regard to histopathological findings of placentas, minimal hypoxic damage (MHD) significantly more frequently found in the groups with pre-eclampsia and IUGR than in the group with uncomplicated pregnancy. The difference between the groups with pre-eclampsia and IUGR was also significant (P < 0.01).III- Infarcts (regardless of their number) were found significantly more common in pre-eclampsia group. There was no difference between the groups in the prevalence of solitary infracts, but multiple infracts were significantly more common in pre-eclampsia group than in IUGR group.IV- At increased UARI, histopathological findings of placentas showed that minimal hypoxic damage was significantly more frequent in the group of placentas with IUGR.V- In the presence of normal UARI, there was statistically no significant difference between the groups in the prevalence of minimal hypoxic damage.VI- The comparison of placental findings in the presence of increased and normal UARI regardless of the complication of pregnancy showed that minimal hypoxic damage and infracts were significantly more frequently seen in the placentas with increased UARI.VII- As regard perinatal outcome, the present study showed that the presence of abnormal uterine artery Doppler velocimetry was associated with significantly higher rate of preterm delivery.VIII- The presence of abnormal uterine artery Doppler velocimetry was associated with significantly higher rate of neonate in need of NICU admission,Conclusion1- The hypoxic changes occurred significantly more frequently in placentas From pregnancies complicated with pre-eclampsia and IUGR than in those From uncomplicated pregnancy.2- The presence of Abnormal Doppler velocimetry of the uterine arteries in pregnancies with fetal intrauterine growth restriction and pregnancies with severe pre eclampsia, may be in fact an important indicator of hypoxic or ischemic placental lesions.3- Because there are close relationship between IUGR, pre-eclampsia and impaired trophoblast invasion, the pregnancies with high uterine artery RI and persistent early diastolic notch, should be observed for fetal morbidity and mortality.In normal human gestations during the first and the second trimester, the uterine spiral arteries are converted into utero-placental arteries (high capacity/low resistance vessels) through a replacement of the muscolo-elastic components of the arterial walls. The physiological changes in the spiral arteries are revealed in an increase of the end diastolic component of the uterine blood flow. This can be easily detected by Doppler velocimetry of the uterine arteries and its branches (Ferrazzi et al., 1999).Ischemic changes occur more frequently in the placentas from women whose pregnancy is complicated with preeclampsia (PET) or intrauterine growth restriction (IUGR) than in those with other complications of pregnancy (Hofstatter et al., 1996).It has long been assumed that in insufficient uterine, placental and fetal circulations result in adverse pregnancy outcome and these abnormalities can be defined with the use of Doppler ultra sonography. Indeed, observational studies have clearly established an association between abnormal velocity waveforms and adverse perinatal outcome such as intrauterine growth restriction, foetal asphyxia and perinatal mortality (North et al., 1999).This study was done on 150 primigravida, sure of dates, in the third trimester with singleton pregnancy attending ante-natal clinic and delivery ward at Obstetrics and Gynecology departments and Pathology departments at Zagazig University Hospitals. They were divided into three groups, 50 cases each.(1) The control group ( Normal pregnancy):Healthy pregnant women without medical or obstetric complications and all laboratory investigations were normal.(II) Patients with severe pre-eclampsia:(III) Patients with Intra-uterine growth restriction:This group included pregnancies complicated with IUGR, but without any symptoms of pre-eclampsia or pre-existing hypertension.All patients were subjected to:I- History, general and obstetric examinations.II- Routine laboratory investigations.III- Ultrasonographic and Doppler studies included uterine artery Doppler velocimetry.IV- Histopathology of the placenta.All cases were evaluated for the assessment of:* Maternal complications.* Mode of delivery.* Perinatal outcome.The correlation between uterine artery Doppler indices and histopathologic changes of placentas was studied and the data obtained were collected, tabulated and statistically analyzed.The results of the present study showed:I- Uterine artery Doppler indices were significantly higher in PET and IUGR groups than control group.II- As regard to histopathological findings of placentas, minimal hypoxic damage (MHD) significantly more frequently found in the groups with pre-eclampsia and IUGR than in the group with uncomplicated pregnancy. The difference between the groups with pre-eclampsia and IUGR was also significant (P < 0.01).III- Infarcts (regardless of their number) were found significantly more common in pre-eclampsia group. There was no difference between the groups in the prevalence of solitary infracts, but multiple infracts were significantly more common in pre-eclampsia group than in IUGR group.IV- At increased UARI, histopathological findings of placentas showed that minimal hypoxic damage was significantly more frequent in the group of placentas with IUGR.V- In the presence of normal UARI, there was statistically no significant difference between the groups in the prevalence of minimal hypoxic damage.VI- The comparison of placental findings in the presence of increased and normal UARI regardless of the complication of pregnancy showed that minimal hypoxic damage and infracts were significantly more frequently seen in the placentas with increased UARI.VII- As regard perinatal outcome, the present study showed that the presence of abnormal uterine artery Doppler velocimetry was associated with significantly higher rate of preterm delivery.VIII- The presence of abnormal uterine artery Doppler velocimetry was associated with significantly higher rate of neonate in need of NICU admission,Conclusion1- The hypoxic changes occurred significantly more frequently in placentas From pregnancies complicated with pre-eclampsia and IUGR than in those From uncomplicated pregnancy.2- The presence of Abnormal Doppler velocimetry of the uterine arteries in pregnancies with fetal intrauterine growth restriction and pregnancies with severe pre eclampsia, may be in fact an important indicator of hypoxic or ischemic placental lesions.3- Because there are close relationship between IUGR, pre-eclampsia and impaired trophoblast invasion, the pregnancies with high uterine artery RI and persistent early diastolic notch, should be observed for fetal morbidity and mortality.