When testing a new vaccine or conducting other research, scientists should take participants’ menstrual cycles into account, 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 demonstrated that the immune system of the vagina varies depending on the stage of the menstrual cycle. The analysis identified 53 distinct messages that immune cells send to each other.
These findings could guide scientists in developing vaccines and treatments for infectious diseases.
Levels of key immune signaling molecules in the vagina “undergo clear and consistent fluctuations” during the menstrual cycle, the study published on Wednesday found.
The primary goal of the study was to build a comprehensive view of immune system-related communication in the vagina and cervix during the menstrual cycle, said Sean Hughes, a researcher in obstetrics and gynecology at the College of Medicine from the University of Washington.
The finding suggests that researchers should consider the stage of a study participant’s menstrual cycle when testing a new vaccine or conducting other investigations, Hughes said.
“Scientists should design their studies to ensure that measurements are taken in all participants at the same stage of the cycle,” said lead author Dr.r 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 another, Hughes suggested.