Progesterone, fluid, and electrolytes in premenstrual syndrome.

Changes in mood, plasma progesterone concentration, urinary volume, sodium excretion, sodium:potassium ratio, and body weight during the menstrual cycle were determined in 18 women with premenstrual syndrome and 10 symptomless (control group) women. Plasma progesterone concentration was higher in the women with symptoms during the postovulatory phase of the cycle, and the peak progesterone concentration appeared earlier. The changes in progesterone concentration were accompanied by a natriuresis and diuresis that fell towards preovulatory values in the premenstrual phase. Sodium retention was not confined to any definite period. Mood symptoms occurred after the changes in progesterone and electrolyte concentrations. Progesterone deficiency is probably not the cause of premenstrual syndrome. Thus treatment with progesterone is probably illogical unless a deficiency is detected. Treatment should be aimed at preventing the natriuretic effect of progesterone in the postovulatory phase and the sodium-retaining and water-retaining effects of aldosterone in the premenstrual phase.