The aim of the study was to detect the regulated in development and DNA responses (REDD1) in human placentas throughout different gestational ages (GAs) and to correlate REDD1 with preeclampsia (PE). In experiments, REDD1 messenger RNA and protein expression levels throughout the gestation were determined using immunohistochemistry, quantitative reverse transcriptase polymerase chain reaction, and Western blot. Furthermore, REDD1 protein levels in placenta were also compared between normal outcome pregnancies (n = 20, GA >37 weeks) and PE pregnancies (n = 29), which includes early onset PE; n = 15, GA: 24-33 weeks) and late onset PE (n = 14, GA: 34-39 weeks) by Western blot. As a result, REDD1 protein was predominantly observed in the cytoplasm of trophoblasts. Moreover, higher levels of REDD1 were found not only at earlier gestational stage but also in the PE groups (P < .05). In conclusion, REDD1 may play an important role in maintaining the normal function of placenta during various stages of gestation and predicted that the increase in REDD1 is related to the pathogenesis of PE.