Hi Midi! I am due for my period in a week, and I noticed that I always get severe heartburn at this time in my cycle ( well...ever scince I got the lovely mirena...) and it usually goes away once my period starts. If you check the hormone menstual chart, 1 week before your period is the peak of progesterone, and it starts to drop off a few days before the period starts...interesting. I googled heartburn and pms and came up with nothing. I would think more women would have this as a pms symptom, especially scince 60% of women report heartburn during pregnancy on web md, and that site states that it happens not only from the baby's position, but also from the progesterone. Why are doctors so quick to admit heartburn is possible from the progesterone in pregnancy, but not the elevated progesterone before your period , or the constant level of progesterone in the mirena??