THE MENSTRUAL-CYCLE AND RAYNAUDS-PHENOMENON

Fluctuations in female sex hormones may be responsible for the high pr evalence of Raynaud's phenomenon (RP) observed in premenopausal women. These hormones are known to act on central and peripheral thermorecep tors. In an attempt to establish whether cold sensitivity is altered d uring the menstrual cycle 50 premenopausal women were investigated. Of these, 26 had primary RP and 24 acted as controls. Each subject was e xposed to environmental heating and cooling at three stages of the men strual cycle to coincide with peaks and troughs in hormone levels. The se stages were menstruation, periovulation, and during the midluteal p hase. Finger hemodynamics was assessed by means of venous occlusion st rain gauge plethysmography and fingertip temperature. Core temperature was assessed with an oral thermocouple. The results show that cold se nsitivity was altered during the menstrual cycle in both groups with t he fastest finger rewarming pattern during menstruation. Moreover, a s ignificant difference was observed in core temperature between the two groups during the midluteal phase. As a group, subjects with RP faile d to show a significant rise in core temperature following ovulation. The authors conclude that the menstrual cycle is associated with chang es in the effect of cold on digital blood flow.