Two surprising health benefits of the pill, unrelated to birth control, discovered

Being on the pill might provide you more protection than just against pregnancy. The female sex hormone progesterone – contained in most forms of hormone-based birth control – has shown in a new study on mice to stave off the worst effects of influenza infection and help damaged lung cells to heal more quickly.

Researchers from the Johns Hopkins Bloomberg School of Public Health, reporting their findings in the journal PLOS Pathogens, suggest that sex hormones have an effect far beyond the reproductive system and that progesterone may one day be a viable flu treatment for women.

In the study, some female mice received progesterone implants while others didn’t. The mice were then infected with influenza A virus. Both sets of mice became ill, but those which had the implants had less pulmonary inflammation, better lung function and saw the damage to their lung cells repaired more quickly.

Progesterone was found to be protective against the more serious effects of the flu by increasing the production of a protein called amphiregulin by the cells lining the lungs. When the researchers bred mice that were depleted of amphiregulin, the protective effects of progesterone disappeared as well.

Study leader Sabra Klein, an associate professor in the school’s department of molecular microbiology and immunology, says there is no scientific data to date showing whether progesterone in humans has any relationship to flu severity. To understand this link better, Klein says Johns Hopkins colleagues doing flu surveillance in humans have added questions about specific forms of birth control to their questionnaires.