Change in haemodynamic profile during phases of the menstrual cycle

In light of evidence that female reproductive hormones may help to protect against the development of cardiovascular disease in women, several studies have examined blood pressure level during the menstrual cycle. However, because the majority of studies have found that blood pressure is unaffected by phases of the menstrual cycle, it has been suggested that changes in underlying haemodynamics may occur which are not evident in measurements of blood pressure. The present study examined blood pressure, heart rate, cardiac output, total peripheral resistance, and salivary cortisol during the follicular and luteal phases of the menstrual cycle in women at rest and during 'stress' (mental arithmetic). Although menstrual phase had no significant effect on blood pressure and heart rate, cardiac output was higher and total peripheral resistance lower during the follicular phase. Menstrual phase did not have a potentiating effect on reactivity to the stressor. The particular pattern of effects, especially the observed attenuation in vascular tone during the follicular phase, is consistent with the suggestion that changes in hormonal milieu during the menstrual cycle may help to protect women against the development of cardiovascular disease.