Endometrial microbial colonization and plasma cell endometritis after spontaneous or indicated preterm versus term delivery

Objective This study was undertaken to determine whether endometrial microbial colonization or plasma cell endometritis is increased after spontaneous versus indicated preterm delivery or a spontaneous term delivery. Study design Postpartum, endometrial specimens were obtained after a spontaneous (mean 83, ± 17.6 days) or indicated (mean 83, ± 16.7 days) preterm delivery before 34 weeksʹ gestation and after a spontaneous term delivery (mean 82, ± 15.7 days; P = .980). Cultures for aerobic and anaerobic bacteria, Trichomonas vaginalis, and genital mycoplasmas were performed. Histologic endometritis was defined as the presence of plasma cells. Results The study population (n = 820) was 71% black, 29% white, 69% unmarried, and 31% had less than 12 years of education. Endometrial cultures were positive for at least 1 microorganism in 82% of the women. No significant difference in positive endometrial cultures were observed among women after a spontaneous versus an indicated preterm delivery (85% vs 79%, P = .102), or a spontaneous preterm versus a spontaneous term delivery (85% vs 81%, P = .123). Plasma cell endometritis was present in 39% of 506 specimens sufficient for histologic examination and was also similar in the three groups (P = .160). Conclusion Microbial colonization of the endometrium and plasma cell endometritis are similar 3 months after spontaneous or indicated preterm or term births. Therefore, chronic infection and inflammation of the endometrium (documented at 3 months postpartum) do not appear to be risk factors for subsequent delivery in women with a prior spontaneous delivery less than 34 weeksʹ gestation.