Objectives: To assess the pendrin expression density on placental bed biopsies from preeclampsia cases in comparison with healthy term controls.

Material and Methods: A prospective case-control study with 106 placental bed biopsies obtained during cesarean deliveries. Pendrin expression was evaluated by immunohistochemical staining in different hypertensive disorders of pregnancy.

Results: Pendrin immunostaining frequency was higher in the hypertensive disorders group (p:0.024), which was a result of the high frequency in the early-onset preeclampsia group. Uterine artery pulsatility indices were higher in pendrin positive patients than in the negatives in the case group. Gravidity was not found to affect the pendrin expression frequency in the placental bed.

Conclusions: Placental ischemia seems to be an important determinant of pendrin expression in pregnant decidua. Increased pendrin density in early-onset preeclampsia could be a pathogenetic mechanism in or a part of the adaptational response to the development of the hypertension.