birth control
"I was on Jolivette for over a year.  The first three months it was great; lighter periods, less PMS, no complaints.  After that grace period, it was all downhill.  I took it at the EXACT same time daily (down to the minute!) and I ended up with two long periods a month! One month I would have a regular period and the next I would have another period two weeks after my first.  It was frustrating to say the least. "