The Effects of the Female Hormones on Cerebral Perfusion

This study is investigating how female hormones — particularly those affected by birth control pills — influence blood flow to the brain. It uses MRI brain scans to compare women using hormonal contraception to those who are not. **You may be eligible if...** - You are a university student (bachelor's or master's level) - You have not been using contraception for at least 3 months, OR you are using a specific low-dose contraceptive pill called Deso20 **You may NOT be eligible if...** - You have not given informed consent - You cannot have an MRI scan (e.g., due to metal implants) - You have claustrophobia (fear of enclosed spaces) - You are pregnant or breastfeeding - You have a chronic illness or take regular medication - You smoke, use drugs, or have a history of substance abuse Talk to your doctor to see if this trial is right for you.