Microbial load and composition of intrauterine device string correlates with symptomatic removals in parous women

A contraceptive intrauterine device (IUD) is a US Food and Drug Administration (FDA) approved method of contraception that is effective and generally well tolerated by patients. However, reports show that IUDs might be associated with inflammation, leading to symptoms like abnormal bleeding and pelvic pain. Pelvic inflammation potentially could be linked to IUD pathogenic biofilm colonization. However, the role of non-pathological microbial communities in this context is not well understood. The aim of the present observational study was to describe the microbiome of the IUD string located in the vagina and cervix in patients with and without IUD related complications. Patients being seen for the removal of their IUD were identified for this study and were grouped according to removal for ‘asymptomatic’ or ‘symptomatic’ reasons. Asymptomatic removals included IUD expiration and desire to conceive while symptomatic removals stemmed from patient complaints, including abnormal bleeding, pelvic pain, and vaginitis. The IUD strings were sent for microbiome profiling by 16S ribosomal ribonucleic acid (rRNA) gene sequencing to characterize bacterial composition and universal 16S quantitative polymerase chain reaction (qPCR) to estimate bacterial bioburden. Microbial composition was compared to determine if symptomatic IUD removal was associated with altered bacterial load, diversity, or composition, with an emphasis on Lactobacillus and non-Lactobacillus abundance. Asymptomatic removals (group A, n = 8) had higher parity (p = 0.012) while relative abundance of Lactobacilli did not differ between groups (p = 0.57). Group A demonstrated a higher abundance of Lactobacillus reuteri compared to symptomatic removals (group S, n = 5), which showed increased overall bacterial load (p = 0.011) and a greater relative abundance of non-Lactobacillus species (p = 0.054), including potentially pathogenic genera such as Fusobacterium and Haemophilus. This study revealed differences in bacterial populations associated with symptomatic IUD removal with a higher overall bacterial burden and abundance of non-Lactobacillus genera. Though the current study is not powered to make conclusions on whether different types of IUDs have differential microbiota or how IUD type relates to complications, these results suggest that the microbiome may contribute. Future research should investigate bacterial composition through the duration of IUD use as well as the variation of the bacterial composition on the different components of the IUD device and explore the potential of targeted intervention with probiotics or antibiotics to prevent or reduce complications associated with IUD contraception.