Here is what somebody on another ttc board shared about light therapy. It was a quote from a book I think, but not sure which book
""'As far back as the 1960s, researchers found that light therapy could normalize long menstrual cycles,' says Dr. George Brainard, PhD, professor of neurology and director of the light research program at Jefferson Medical College in Philadelphia. 'In recent years, a research team working with Daniel Kripke, M.D. at the University of California at San Diego repeated those studies with good results.'
"In Dr. Kripke's studies, it was shown that exposure to sunlight for three days during the beginning to the middle of the menstrual cycle significantly shortened and normalized long, irregular menstrual cycles.
"'Begin the day with a 30-minute walk or light-box session,' says Dr. Brenda Byrne, PhD, director of the Seasonal Affective Disorder Clinic affiliated with the light research program at Jefferson Medical College.
"A study done in Switzerland showed that a daily 30-minute walk in the morning--even on a cloudy morning--is as effective for treating depression disorders and menstrual cycle irregularities as using a special light-box."
For me it worked amazingly well the last cycle. I just looked up my cycle length and found that they were up to 39 days. So ovulating on day 12 instead was a nice improvement! Curious to see what will happen this cycle.
There is another type of light therapy that I have never tried. Basically it requires that you sleep in total darkness for your cycle, apart from day 14, 15, and 16, when you leave some light on during the night. You are supposed to ovulate on one of those days. I don't have personal experience with it though, so can't tell how effective it would be. If anybody does try it, I would be interested in the results.