I just started on Prometrium 200mg (bio-identical progesterone) for this very thing. I'm nearing 41 and have had stupid short cycles (with long bleeds) for at least 5-6 years. I'm not loving some early side-effects of the med, but didn't love the dumb cycles, either. I also have an ovarian cyst--kiwi-sized! I may drop down to 100mg after I finish the 3 cycles of the meds I have, if the side-effects don't decrease a bit as I adapt. I'm crazy sleepy and dealing with some vertigo.