When testing a new vaccine or conducting other research, scientists should consider participants’ menstrual cycles, a study has found.
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A meta-analysis of 32 studies published Wednesday in the journal BMC Medicine by a team led by the University of Washington found that the immune system in the vagina varies by stage of the menstrual cycle. The analysis identified 53 different messages that immune cells send to each other.
These results could guide scientists in developing vaccines and treatments for infectious diseases.
Levels of key immune signaling molecules in the vagina “undergo marked and consistent fluctuations throughout the menstrual cycle,” according to the study published Wednesday.
The primary goal of the study is to provide a comprehensive overview of immune-related communication in the vagina and cervix during the menstrual cycle, said Sean Hughes, an obstetrics and gynecology researcher at the University of Washington College of Medicine.
The finding suggests that researchers should consider the stage of a study participant’s menstrual cycle when testing a new vaccine or conducting other research, Hughes said.
“Researchers should design their studies to ensure that measurements are taken at the same stage of the cycle in all participants,” said lead author Dr. Florian Hladik, Professor of Obstetrics and Gynecology at the University of Washington.
Overall, the difference between the follicular and luteal phases could mean that vaccinations and other interventions would be more effective in one phase than the other, Hughes suggested.