The relation of increased uterine artery blood flow resistance and impaired trophoblast invasion in pre-eclamptic pregnancies

Objective: To assess the association between histopathologically confirmed vascular abnormalities developed during pre-eclampsia and abnormal arterial blood flows recorded during Doppler sonographies. Materials and methods: From pregnant women who attended our clinic between 01/03/2002 and 01/07/2002, a detailed medical history was obtained and routine biochemical blood tests, fetal ultrasonography and UA Doppler scans were performed. In addition, from pre-eclamptic and normal pregnant women who underwent cesarean sections, placental bed biopsies were taken. Thirty two pre-eclamptic [12 mild, 20 severe cases according to American College of Obstetricians and Gynecologogists (ACOG) criteria] cases and as a control group 20 normal pregnancies were included in the study. In our study trophoblast invasion into decidual spiral arteries was observed in 75% of mild (9/12), and 55% of severe (11/20) pre-eclampsias. In the control group all the cases demonstrated trophoblast invasion in decidual spiral arteries. Trophoblast invasion in myometrial spiral arteries was noted in 50% (6/12) of mild and 25% (5/20) of severe pre-eclamptic pregnancies. It was seen in 16 cases out of 20 (80%) pregnancies. In the control group, decidual spiral artery invasion manifests significant differences (P<0.01) among groups studied. Invasion in decidual spiral arteries was seen in all normal pregnancies of the control group. There is not any significant difference between mild and severely pre-eclamptic groups (P>0.05). Conclusion: Doppler ultrasonography is not only a non-invasive method for evaluating fetal status in pre-eclamptic pregnancies, but it also correlates with partial trophoblastic invasion in spiral arteries, which contributes to the pathophysiologic mechanisms involved in pre-eclampsia.