Pressor response during normal menstrual cycle

Abstract

Aims:To study the blood pressure variations during different phases of the menstrual cycle using a set of autonomic function tests,Methods:The study included30 eumenorrheic,normal,normotensive,healthy females aged 18-30 yrs and a set of autonomic function tests were done to assess the pressor response during the three phases-menstrual phase,follicular phase and luteal phase of a single normal menstrual cycle.The subjects were selected based on predetermined exclusion-inclusion criteria.No controls of any kind (males or menopausal females) were included as the aim of the study was to compare pressor response among the three phases of a single menstrual cycle.Results:Across the menstrual cycle there was varied pressor response with higher values towards the luteal phase,when compared to the follicular and the menstrual phases.The statistically significant differences in the blood pressure parameters,resting blood pressure,postural variation in blood pressure and blood pressure response to cold pressor test were found between all he phases,with higher values towards the luteal phase.The results were obtained using ANOVA and student-t-test,to study the significance of study parameters on continous scale within each phases.Conclusion:There was varied pressor response across the menstrual cycle with higher values towards the luteal phase,as observed by the increased sympathetic outflow in the luteal phase compared to the increased parasympathetic outflow in the follicular phase.The baroreflex regulation of autonomic functions induced by posture changes is also modified during the normal,regular menstrual cycle.This altered regulation of the autonomic tone during the normal,regular menstrual cycle can be attributed to the cardio-protective effects of oestrogen in healthy young females in contrast to menopausal females.