Effect of pretreatment with a levonorgestrel-releasing intrauterine system on IVF and vitrified-warmed embryo transfer outcomes in women with adenomyosis.

RESEARCH QUESTION: Does the use of a levonorgestrel-releasing intrauterine system (LNG-IUS) improve the ongoing pregnancy rate of vitrified-warmed embryo transfer in women with adenomyosis undergoing IVF?

DESIGN: This retrospective study included 358 women with adenomyosis undergoing IVF. Of these, 134 women were enrolled in the LNG-IUS group and another 224 women were in the control group. All women were screened for adenomyosis by transvaginal ultrasound and magnetic resonance imaging (MRI). There was no significant difference in the ages of women, FSH, cause of infertility, body mass index, total dose of gonadotrophin used and number of oocytes collected between the two groups. All comparisons performed were between patients undergoing vitrified-warmed embryo transfer.

RESULTS: Statistical differences were found in the ongoing pregnancy rates (41.8% vs 29.5%, P = 0.017) between the LNG-IUS group and control group. Logistic regression analysis showed that the odds ratio (OR) of ongoing pregnancy was significantly increased with LNG-IUS usage (adjusted OR = 1.628, 95% confidence interval 1.011-2.622). Also, differences were found in implantation rates (32.1% vs 22.1%, P = 0.005) and clinical pregnancy rates (44% versus 33.5%, P = 0.045) between the LNG-IUS group and control group.

CONCLUSIONS: The results of this study offer some support for evaluating the effect of pretreatment with LNG-IUS in women with adenomyosis in future randomized controlled trials.