Elevated percentage of CD3T cells and pregnancy outcome in women with recurrent pregnancy loss.

Background: Even though the immune factor is not yet established as a cause of recurrent pregnancy loss (RPL), tons of other studies have shown that a significant proportion of immune abnormalities exist in RPL.

Methods: We conducted a retrospective cohort study with 850 women who were diagnosed with RPL. The percentages of CD3, CD3CD4 and CD3CD8T cells of each participant, detected by flow cytometry, were obtained before pregnancy and at 6 weeks of gestation as part of their routine medical examination.

Results: Peripheral blood CD3 T cells prior to pregnancy (at baseline), increased significantly in women who had a miscarriage compared with the subsequent live birth group. Moreover, the percentage of CD3 and CD3CD4T cells during pregnancy increased significantly as compared with the baseline level. After adjusting for potential confounders, the multiple regression equation showed that the CD3 T cells <67.84% was associated with the risk of miscarriage (OR 1.05, 95% CI, 1.01 to 1.11, p = .04). Additionally, a nonlinear relationship was observed between the percentage of CD3T cells and the risk of miscarriage.

Conclusions: The risk of miscarriage increased as the percentage of population with CD3+ value below 67.84% has increased, nevertheless, the miscarriage risk did not increase further when the level of CD3T cells was >67.84%.