Endometrial CD38 and CD138 positivity associated with ectopic pregnancy history

Women with a history of ectopic pregnancy had higher rates of endometrial CD38 and/or CD138 positivity than a control group of women with recurrent spontaneous abortion, according to a retrospective study. The reported prevalence of positive cells was 54.1% among women with ectopic pregnancy who had never undergone an intrauterine operation, 72.5% among those with ectopic pregnancy and at least one prior intrauterine operation, and 28.1% among controls.

The researchers analyzed three groups totaling 609 women. Group A included 98 women with a history of ectopic pregnancy but no prior intrauterine operation. Group B included 244 women with a history of ectopic pregnancy and at least one intrauterine operation. The control group comprised 267 women with recurrent spontaneous abortion. Endometrial CD38 and/or CD138-positive cells were present in 53 of 98 women in Group A, 177 of 244 in Group B, and 75 of 267 controls. The authors reported that positivity was significantly more frequent in the endometrium of women with a history of ectopic pregnancy than in the recurrent-spontaneous-abortion control group.

CD38 and CD138 were examined as markers associated with chronic endometritis. Within the ectopic-pregnancy groups, positivity was more common among women who had undergone an intrauterine operation: 177 of 244 women in Group B were positive for CD38 and/or CD138, compared with 53 of 98 in Group A. This subgroup difference was observed in the retrospective data, but the study did not establish that intrauterine operations caused the higher positivity rate. Likewise, the analysis identified an association between endometrial marker status and ectopic-pregnancy history rather than proving a causal role for chronic endometritis in ectopic pregnancy.

The findings are consistent with the study authors’ hypothesis that chronic endometritis may be an underlying pathogenic factor contributing to ectopic pregnancy. However, the evidence comes from a retrospective comparison with unequal group sizes, and the control population had recurrent spontaneous abortion rather than no reproductive history. The design also cannot determine whether CD38 and CD138 positivity was present before the ectopic pregnancies, developed afterward, or reflected other differences between the groups. The study therefore supports an association worthy of further investigation, not a demonstrated mechanism, diagnostic tool, preventive measure, or clinical benefit.

Subject of Research: Endometrial CD38 and CD138 positivity, chronic endometritis markers, and ectopic pregnancy history in a retrospective cohort

Article Title: Increased Endometrial CD38 and CD138 Positivity in Women with Ectopic Pregnancy History: A Retrospective Study

Article References: Li, Y., Li, Y., Chen, D., Xie, X., Zhang, C., Zhong, X., & Xie, M. (2026). Increased Endometrial CD38 and CD138 Positivity in Women with Ectopic Pregnancy History: A Retrospective Study. Reproductive Sciences. https://doi.org/10.1007/s43032-026-02246-w

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DOI: 10.1007/s43032-026-02246-w

Keywords: ectopic pregnancy, endometrium, CD38, CD138, chronic endometritis, retrospective study, reproductive health, intrauterine procedures, recurrent spontaneous abortion, inflammatory markers, Increased, Endometrial