effects of levonorgestrel releasing intrauterine device on menstrual bleeding pattern, endometrial thickness and uterine vasculature

The study aimed to evaluate the effect of the levonorgestrel releasing intrauterine device [LNG-IUD] on menstrual bleeding pattern, endometrial thickness and uterine vasculature. The study was a prospective controlled study evaluating the effects of LNG-IUD compared with the copper intrauterine device [IUD]. Twenty women carrying LNG-IUS [group I] were compared with thirty women carrying copper IUD in a control group [group II]. Clinical measures of menstrual bleeding, endometrial thickness and Doppler flow of the cervical branch of the uterine artery and spiral artery were evaluated and compared between the two groups. Doppler flow in the cervical branch of the uterine artery did not reveal any changes between the groups I, II [resistance index 0.59 +/- 0.08 and 0.6 +/- 0.09 respectively]. Endometrial thickness was significantly thinner in group I compared with group II [3.9 +/- 1.21 and 7.5 +/- 2.94mm respectively]. Subendometrial flow in the spiral artery was detected in six women only of group I [30%] and in all women of group II [100%]. The present study offers explanation for the change of the menstrual bleeding pattern [specially amenorrhea and oligomenorrhoea] in LNG-IUD users, i.e. a local progestational effect on the endometrium with no change in the uterine vasculature. This adds to the therapeutic value of the device and would lessen the discontinuation rate specially if properly addressed to women in the pre-contraceptive examination