The pill could be changing your brain. That's the conclusion of a new study published in Human Brain Mapping which looked at whether the steroid hormones in oral contraceptive pills could affect brain structure and function.
The research compared the brains of 90 women, 44 of whom used oral contraceptives. They found the group who used the pill had "significantly lower cortical thickness measurements" in two parts of the brain, the lateral orbitofrontal cortex (which affects decision making) and the posterior cigulate cortex (no one is really sure what this does).
The study's lead author Nicole Petersen told the Huffington Post that the emotional side effects some women had reported while taking the pill may be related to these changes in the brain structure, although it was not clear if the changes were long term.
"It's possible that this change in the lateral orbitofrontal cortex may be related to the emotional changes that some women experience when using birth control pills," she said. "We need to do more studies to find out what behaviours might be changed, but this study gives us some targets to start with, and I think the first place to look is at the effect of birth control pills on regulating emotions."