Premenstrual Syndrome (PMS) starts between five to eleven days before the menstrual cycle and experts think it happens from the change in the hormones progesterone and estrogen, explains Dr. Debra Kenward, Obstetrician and Gynecologist with Baptist Health South Florida.
In some cases, PMS triggers changes in the renal system (renin-angiotensin system), allowing water retention, bloating and inflammation. Also the serotonin system changes, which can affect women sleep and moods, the expert describes.
Dr. Kenward also says 40% of people have symptoms of PMS (physical, emotional or both) and 5% of people have a premenstrual dysphoric disorder (a form of depression).