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.