Abstract

Objective To define the decidual microenvironment in euploid and aneuploid missed abortions and elective termination of pregnancies. Design Prospective, multicenter, observational study. Setting Tertiary hospital and descriptive analysis of transcriptomic data. Patient(s) A total of 34 patients experienced abortions, including 6 women who underwent elective terminations of pregnancy of unplanned pregnancies and 28 cases with missed abortions. All patients underwent their operations from Sep, 2021 to Sep, 2022. Intervention(s) All women underwent villous copy number variation sequencing. Meanwhile, single-cell RNA sequencing were performed in the decidual tissues of 16 women, and reverse transcription quantitative polymerase chain reaction were performed in the decidual tissues of 18 women. Main Outcome Measure(s) Single-cell RNA sequencing was used to explore the changes in the microenvironment of decidual tissues in abortions. Result(s) Single-cell RNA sequencing indicated that the microenvironment of the decidual tissue of the missed-abortion group was altered, and that the stromal cells (SCs), natural killer cells, macrophages, and epithelial cells all reflected functional imbalances compared with the elective terminations of pregnancy group. We also noted a correlation between the proportion of senescent SCs and chromosomal abnormalities in missed-abortion embryos. The proportion of senescent decidual SCs in the decidual tissue of missed-abortion patients with common chromosomal abnormalities of the fetus was higher, and this was not conducive to fetal growth and was closely related to missed abortion. In addition, we ascertained that the strength of the HLA-KIR interaction between NK1 and NK2 subsets and non-senescent stromal cell subsets in the missed abortion decidual tissues was weakened, potentially playing a role in the occurrence of missed abortion. Concl