Artificial insemination: A combination of bacteria could predict success, current tests lack a scientific basis
Common tests designed to predict the success of artificial insemination are often inaccurate. This conclusion is drawn from a new study conducted by the University Hospital Schleswig-Holstein (UKSH), the Universität zu Lübeck, and the German Center for Infection Research (DZIF).
Previous predictive models examine bacterial colonization of the vagina and categorize it into broad bacterial patterns. However, according to the study, this classification—on which commercial microbiome tests are also based—is not reliable.
Instead, the research team identified two specific bacteria that negatively influenced treatment success: Lactobacillus iners and Ureaplasma parvum. In patients in whom both bacteria were detectable simultaneously and in high concentrations, the chances of successful embryo implantation and a live birth dropped dramatically.
Criticism of Commercial Services
“Our data contradict the assumption that simply classifying the vaginal microbiome into the bacterial patterns proposed to date allows for clinically relevant predictions of pregnancy rates,” says Prof. Georg Griesinger, Director of the University Fertility Center at UKSH, Lübeck Campus, and principal investigator. “Couples should therefore not rely on the predictive power of analyses based solely on these simplistic categories.”
“The specific bacterial signature we have identified could serve as a significantly more precise diagnostic tool in the future than previous models,” explains Dr. Mariia Lupatsii, co-first author of the study. “If models are marketed without clinical validation, we risk making wrong treatment decisions.”
“Our work shows that we need to move away from generalizing patterns and toward analyzing specific microbial interactions,” says the other first author, Dr. Simon Graspeuntner. “Identifying clinically validated bacterial communities could help reduce the number of necessary treatment cycles in the future and protect couples from false expectations.”
Infertility affects many couples: According to estimates, 15 to 20 percent of all couples of childbearing age in Germany are affected by it at some point in their lives.
The study, published in the journal Human Reproduction Open, examined 266 patients. It showed that neither the classification into bacterial patterns—the so-called “Community State Types categories”—nor the diversity of bacterial species (alpha diversity) correlated statistically with the occurrence of a pregnancy or a live birth.
