By analyze the expression levels of immune cells and cytokines secreted by preeclampsia patients before and after delivery. Furthermore, to determine the inflammatory and immunological mechanism responsible for preeclampsia, to provide better future prevention and treatment.Twenty-one preeclampsia-diagnosed pregnant women were involved in this study as an observation group. Twenty pregnant women with no history of PE, age-matched, were added to the control group. Thirty NP women, age-matched were included as the reference. The levels of cytokines secreted by T, B, NK and Treg immune cells and Th1, Th2 and Th17 cells were detected before and after delivery.The number of CD3 + cells in women without preeclampsia before delivery was not statistically different from that in PE patients, but the number of CD4 + and CD8 + cells was lower than that in women without preeclampsia. After delivery, CD4 + cells were larger than those in pregnant women without preeclampsia, while CD8 + cells were smaller than those in pregnant women without preeclampsia. The level of cytokines secreted by Th1 in pregnant women without preeclampsia before delivery was higher than that in PE patients. The levels of cytokines produced by Th1, Th2 and Th17 cells before and after delivery were higher in pregnant women without preeclampsia than in NP women, while Th2 and Th17 were in PE group.PE patients may reduce CD4 + cells and CD8 + cells, and down-regulate the level of cytokines (especially TNF-β) secreted by Th1 cells to reduce the maternal rejection of embryos, thereby reducing the risk of premature delivery, which is a protective adaptive compensation mechanism in favor of embryos.Copyright © 2023 The Authors. Published by Elsevier B.V. All rights reserved.