A recent study explored the impact of the Mirena levonorgestrel-based hormonal IUD on vaginal microflora, revealing minimal to negligible effects. This comprehensive study involved sampling from Caucasian women over several weeks, identifying 355 bacterial species with Lactobacillus crispatus being the most prevalent. The findings suggest that the Mirena IUD does not significantly alter the vaginal microbiome, maintaining a stable environment post-insertion.