Evidence for altered transcapillary fluid balance in women with the premenstrual syndrome.

Redistribution of body fluids has been suggested as a possible pathophysiological mechanism for the premenstrual syndrome (PMS). To elucidate this hypothesis, transcapillary fluid balance was studied in ten women with well defined PMS. Wick-methods were used for measuring colloid osmotic and hydrostatic interstitial pressures on the thorax and on the leg. The capillary filtration coefficient was measured by strain gauge plethysmography. From the follicular to the luteal phase the interstitial colloid osmotic pressure on the leg was significantly reduced (mean 3.6 mm Hg, p = 0.005), whereas the interstitial colloid osmotic pressure on the thorax remained constant. The capillary filtration coefficient increased 30% (mean 5.3 x 10(-4) ml/min/100 gm/mm Hg, p = 0.04) from the follicular to the luteal phase. No change was observed in body weight. These findings indicate an instability of vascular regulation in women with premenstrual syndrome, and lend support to the hypothesis that redistribution of fluid, rather than water retention, is responsible for the subjective symptoms such as bloatedness, in the premenstrual syndrome.