Background: The presence of regulatory T (Treg) cells in human endometrium is crucial for maintaining immunological homeostasis within the uterus. For this study we decided to evaluate the subpopulations of Treg cells in conditions where a disturbance in the immunological equilibrium in ectopic endometrium and decidua has been observed, such as in cases of ovarian endometriosis (involving local immune cell suppression) and ectopic pregnancy (involving an increase in local immune system activity). We then compared these findings to what we observed in the normal eutopic endometrium of women during the secretory phase of the menstrual cycle (with immune cells under individual control). Methods: The endometrium tissue samples evaluated in our study were obtained from 47 women during one of two kinds of laparoscopic procedures. 16 of the women underwent laparoscopies due to Fallopian tube pregnancies (EP), and 16 due to ovarian endometrioma, while 15 women made up a control group. The presence of regulatory T cells in these tissue samples was evaluated by FACS. Results: In our study, the percentages of FOXP3+ cells within the subpopulation of CD4+ T lymphocytes found in the decidua of the patients treated for Fallopian tube pregnancies were statistically significantly lower than both those observed in the ovarian endometriosis tissue samples and those found in the secretory eutopic endometrium samples of the control group. Conclusion: The disturbance in the immunological equilibrium observed in ectopic endometrium and decidua would seem to be related to the alteration in the Treg cell population that occurs in these ectopic tissues.

Introduction: The participation of immune tolerance during pregnancy was suggested to be an important factor predisposing to the implantation of decidual cells after cesarean section in Pfannenstiel scar. Delivery at term is related to the termination of immune tolerance to fetal antigens that is maintained throughout pregnancy. Substantial proportion of cesarean section deliveries is performed before the onset of true term labor. The aim of this study was to analyze the clinical symptoms of spontaneous beginning of labor in pregnant women in whom cesarean sections were performed and in whom Pfannenstiel scar endometriomas were observed during follow-up. Materials and Methods: We have retrospectively analyzed 81 patients following the surgical removal of scar endometrioma after cesarean section. Obstetrical histories of cesarean sections in the number of 5,370 preceding the occurrence of the scar endometrioma were analyzed. These data were collected in six different Gynecological and Obstetrical wards in Malopolska Province in Poland. Analysis of data was started by the retrospective evaluation of regular uterine contractions, uterine cervix ripening before cesarean section and the indications for surgery. Results: In 67 women from the group of 81 patients cesarean sections were performed with unripe uterine cervix and without the presence of regular uterine contractions. Elective indications for cesarean sections were predominant in this group of women. The relative risk of scar endometriomas occurrence following cesarean sections performed before onset of labor in comparison to cesarean sections following spontaneous onset of labor was statistically significantly higher [RR = 2.16, 95% CI = 1.21–3.83; OR = 2.18, 95% CI = 1.22–3.89]. Conclusions: Cesarean section performed before spontaneous onset of labor may increase substantially the risk of occurrence of scar endometriomas.