I've been on Ortho Evra for almost 3 years now, and within the last three months I've noticed my periods suddenly shortened to like 4 days. They used to start regularly on the day after I took my patch off, now they start a few days later.

Despite being on it regularly for years, my period still occasionally changes. I really don't know why. Before, I was on Ortho Tri-Cyclen, and the same thing would happen every so often. Again, I honestly don't know why. My best guess is a slew of variations we aren't even aware of that effect us, not just the HBC.