Introduction: The pathophysiology of PIH remains unclear. Recently, placental abnormalities are stressed as a possible cause of PIH. Abnormal shallow invasion of trophoblasts, confined to decidua, without involving myometrium is believed to result in reduced uteroplacental perfusion, endothelial injury, and activation of coagulation cascade system. Integrin, one of the adhesive membrane proteins, is expected to be related to the regulation of trophoblasts invasion. Purpose: The purpose of this study is to investigate the expression of adhesion molecules in placenta and the correlation between uterine artery Doppler findings and integrin expressions in the placentas of PIH patients. Subjects: Thirty-six cases of severe PIH patients were enrolled in the study with 10 number of normal control pregnant women. The integrin subunit expressions with immunohistochemical staining were observed in floating villi, maternal-side cytotropholbasts, and fetal-side cytotrophoblasts. Uterine artery Doppler study was also performed, and the S/D ratio was evaluated. Abnormal Doppler findings was defined as S/D ratio≥2.6. Results: Cytoplasmic staining of villi and placental bed cytotrophoblast for the integrin α1 subunit in PIH specimen was weaker than those in normal controls. The expression of integrin β1 subunit was negative for both controls and PIH group. The positive cytoplasmic stain was observed among PIH placenta in contrast to normal control in which the expression of integrin β4 subunit was not detected. The expression of αvβ 3 in trophoblast with PIH was positive staining, but not in control group. Uterine artery Doppler velocimetry was performed in 25 cases with PIH. Trace(+/-) or - staining of integrin α1 subunit were observed in 60.0% of abnormal S/D(≥2.6) group, 20.0% of normal S/D ratio group patients, respectively. Trace or + staining of integrin β4 subunit were observed in 50.0% of abnormal S/D group and 6.7% of normal S/D group and this is in statistically significant. Trace or + staining of integrin αvβ3 subunit were observed 70.0% of abnormal S/D group and 26.7% of normal S/D group, and this statistically significant. Conclusion: In PIH the abnormality in the invasion of cytotrophoblats results in abnormal integrin subunit expression, but it is also correlated to the abnormal uterine artery Doppler velocimetry which shows a S/D ratio of greater than 2.6. Thus, the uterine artery Doppler velocimetry reflects abnormal placentation.