Abstract
Objective. The objective of the present study was to investigate whether or not the presence of irregular bleeding during use of oral contraceptives (OC) is associated with increased cyclooxygenase-2 (COX-2) expression.
Patients and methods. An observational study was carried out in 26 patients who were using gestodene 75 μg/ethinylestradiol 30 μg prior to endometrial resection. The patients were divided into two groups: those with amenorrhea (n = 14) and those who had irregular bleeding (n = 12). The resected endometrium was immunostained for COX-2, Bcl-2 and Ki-67 expression. Routine pathology was carried out using standard hematoxylin–eosin staining.
Results. Irregular bleeding during OC use was associated with strong COX-2 expression in both glandular and superficial epithelium. There were also more patients in this group with irregular endometrial maturation and higher Ki-67 values. Bcl-2 expression, on the other hand, was not affected by the presence of uterine bleeding.
Conclusion. The presence of irregular bleeding during OC use is associated with strong COX-2 expression in the endometrium, thereby suggesting a pivotal role of prostaglandins in this process.