Effect of copper intrauterine device on the cyclooxygenase and inducible nitric oxide synthase expression in the luteal phase endometrium

BackgroundTo evaluate the effect of copper intrauterine device (IUD) on the expression of cyclooxygenase (COX) and inducible nitric oxide synthase (iNOS) in the luteal phase endometrium.Study DesignA prospective clinical study was conducted on 30 women who were willing to use a copper IUD contraception. Endometrial biopsies and blood samples were taken before and 3 months after the insertion of the IUD on Day 3 and Days 20–24 of the cycle. Main outcome measures were to evaluate the effect of copper IUD on uterine artery blood flow using pulsed color Doppler ultrasonography and the relationship of bleeding abnormalities and menstrual pain level with the uterine blood flow, COX-2 and iNOS expression.ResultsOnly the left uterine artery pulsatility and resistance indices decreased statistically significantly (p=.005 and p=.039, respectively). Other Doppler parameters showed no change. Cyclooxygenase-2 expression of both endometrial luminal epithelium (p=.03) and gland epithelium (p=.03) increased significantly. Inducible NOS expression of the endometrial surface epithelium decreased significantly after IUD insertion (p=.01).ConclusionsAlthough COX-2 expression increased 3 months after copper IUD insertion, iNOS expression of the luminal epithelium decreased. Local hypoxia caused by copper and vasoconstrictor prostanoids may play a role in IUD-related menstrual abnormalities.