A comparative study of the levonorgestrel-releasing intrauterine system Mirena versus the Copper T380A intrauterine device during lactation: breast-feeding performance, infant growth and infant development.

Background: Mirena is a levonorgestrel-releasing intrauterine system (LNG-IUS) that provides highly effective and long-acting progestogen-only contraception.

Objective: The objective of this study was to analyze the possible effects of using LNG-20 microg IUS on breast-feeding performance, infant growth and infant development during the first postpartum year as compared with the Copper T380A intrauterine device (Cu T380A IUD).

Design: This study is a prospective, controlled and randomized trial.

Setting: The study was conducted at the Department of Obstetrics and Gynecology, Assiut University Hospital, Egypt.

Methods: Three hundred twenty lactating women asking for initiation of contraception during the early postpartum stage were assigned randomly into two groups, the LNG-20 microg IUS group (n=163) and the Cu T380A group (n=157). The insertions were done 6-8 weeks postpartum. Each participant was followed up at three monthly intervals after insertion and until the first birthday of her baby. During these visits, the breast-feeding pattern was assessed, certain infant physical growth parameters were measured and a set of infant development tests was performed.

Results: No pregnancy occurred in both groups. There were no significant differences in the net continuation rates between the two groups (89.3 for LNG-IUS vs. 90.9 for Cu T380A). The LNG-20 microg IUS group had comparable rates of breast-feeding continuation, complete weaning, full breast-feeding and partial breast-feeding, with the Cu-IUD group. No statistically significant differences were found between groups with regard to all infant physical growth parameters and various infant development tests.

Conclusion: The findings of the current study confirm that the use of LNG-20 microg IUS during the first postpartum year in lactating women provides highly effective and acceptable contraception and does not negatively influence breast-feeding or the growth and development of breast-fed infants.