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Copper Intrauterine Device Affects Vaginal Bacteria and Inflammation

Online publication date: Jan. 30, 2023

Can certain types of birth control alter vaginal health? Researchers in the Center for Global Infectious Disease Research at Seattle Children’s Research Institute found a non-hormonal copper intrauterine device (IUD) causes changes in vaginal bacteria and increases inflammation compared to two other popular hormonal options to prevent pregnancy. This work highlights the various ways that contraceptives affect vaginal health and helps to explain how the microbes and inflammatory response of the female reproductive tract are affected by birth control.

The findings were published in the journal Nature Communications. The paper’s first author, Dr. Bryan Brown, is an investigator in the lab of Dr. Heather Jaspan and an acting assistant professor of infectious diseases at the University of Washington.

The data was generated from 218 South African and Kenyan women enrolled in a substudy of the Evidence for Contraceptive Options and HIV Outcomes (ECHO) Trial, which previously found no significant difference in HIV incidence among 7,829 African women randomized to a depot-medroxyprogesterone acetate injection, a levonorgestrel upper arm implant or the non-hormonal T-380 copper IUD.

Based on those findings, the World Health Organization issued recommendations that women can use any method of contraception, barring medical contraindications, regardless of their HIV risk; however, the main trial did not explore possible interactions between contraceptives and resident bacteria in the female genital tract.

This study evaluated the effect on the vaginal environment of the three methods of contraception after one and six consecutive months of use. Negative effects on the vaginal environment were found in those women using copper IUDs, which may adversely impact sexual and reproductive health. The researchers believe such changes happen because ionic copper released by the IUD may selectively reduce the growth of healthy bacteria, which could enable inflammatory bacteria to abundantly increase. As a result, the body produces inflammatory proteins.

The work expands understanding of how contraceptives affect reproductive health and shows additional factors that may shape a woman’s experience with a given contraceptive or susceptibility to sexually transmitted diseases.

Jaspan, a principal investigator at the research institute and an associate professor of both global health and pediatrics – infectious diseases at the University of Washington, said her lab next plans to study how long the effects will continue to affect women using these birth control options.

“Our study evaluated the effect of each option for six months, but the length of use of these products can be much longer, so determining if these effects persist after a year or several years will be informative,” Brown said. The Jaspan Lab will also examine whether their findings are generalizable to other populations of women, and whether other intrauterine devices have similar effects.

The Jaspan Lab’s Colin Feng, and Drs. Smritee Dabee, Melanie Gasper and Donald Nyangahu also contributed to the findings. Other collaborators include the University of Washington International Clinical Research Center, the University of Cape Town, the University of Witwatersand, and the Kenyan Medical Research Institute.

“As with any work, it takes a tremendous group of talented people at many institutions, including in the clinic and in the laboratory, and this work is a testament to some great international teamwork,” Brown said. “We are also tremendously grateful to all of the women that participated in this study; this work could not have been accomplished without them.”

This research and the ECHO Study were supported by the Bill & Melinda Gates Foundation, the U.S. Agency for International Development, the Swedish International Development Cooperation Agency, the South Africa Medical Research Council, the South African government, the United Nations Population Fund and the National Institute of Child Health and Human Development. 

— Colleen Steelquist