Effect of hysterectomy or LNG-IUS on serum inhibin B levels and ovarian blood flow.

Objectives: Nearly one third of women complain of heavy menstrual bleeding during their reproductive years. Hysterectomy and levonorgestrel-releasing intrauterine system (LNG-IUS) are effective treatment options for menorrhagia. However, the influence of these two treatment modalities on ovarian function remains unclear. The aim of the study was to evaluate the effect of hysterectomy or LNG-IUS on ovarian function.

Methods: Of 107 women, aged 35-49 years, referred for menorrhagia to the University of Helsinki, Finland, 54 were randomised to hysterectomy group and 53 to LNG-IUS group. Serum concentrations of inhibin B were measured at baseline, at 6-month, and at 12-month follow-up visits. The pulsatility indeces (PI) of ovarian and intraovarian arteries were measured by transvaginal ultrasound on the same visits. Changes in outcome measures between the groups were tested by Student's t-test for independent samples and within the group by Wilcoxon signed rank test. To test association between outcome variables and explaining factors a multiple linear regression model was used.

Results: Serum inhibin B concentrations decreased after the first 6 months in both groups (P<0.05). No change was observed in PI of the ovarian arteries in either group. PI of the intraovarian arteries decreased at 6 and 12 months (P<0.05) in the hysterectomy group, which was not seen among LNG-IUS users. Change in PIs between the treatment arms was also significant (P<0.05). In multiple linear regression model treatment modality explained the change in serum inhibin B concentration and the change in PI of intraovarian artery (P<0.05).

Conclusions: Hysterectomy but not LNG-IUS alters intraovarian blood flow and may impair ovarian function.