Effect of Menstrual Cycle Phases on Plasma Lipid and Lipoprotein Levels in Regularly Menstruating Women.

INTRODUCTION: Physiological cyclic variability in levels of sex hormones during a menstrual cycle may possibly have an impact on lipids, lipoprotein levels and therefore on cardiovascular health status of females.

AIM: To ascertain the effect of menstrual cycle phases on the levels of cardiovascular risk predictors i.e., plasma lipids and lipoproteins in healthy menstruating women.

MATERIALS AND METHODS: In the present study, 111 healthy regularly menstruating females aged 15-45 years were examined at two points of a menstrual cycle i.e., in the follicular phase (10th day) and in the luteal phase (22nd day) to find out the plasma levels of lipids and lipoproteins. The data were statistically analysed using paired t-test.

RESULTS: A significant decrease in the mean levels of Total Cholesterol (TC) (p=0.006), Low Density Lipoprotein Cholesterol (LDL-C) (p=0.004), TC/High Density Lipoprotein Cholesterol (HDL-C) (p=0.006), Low Density Lipoprotein Cholesterol (LDL)/HDL (p=0.01), and Triglyceride (TG)/HDL (p=0.02) was observed in the luteal phase compared to the follicular phase while TG (p=0.18), HDL-C (p=0.16). VLDL-C (p=0.17) did not show a significant difference although lower levels were observed in the luteal phase of TG and VLDL-C and higher levels for HDL-C.

CONCLUSION: The present findings reveal high levels of oestrogen in the luteal phase compared to follicular phase of menstrual cycle. Clinicians should take menstrual cycle phase in account when inferring a women biomarker measurement in the analysis of cardiovascular diseases, particularly females possessing marginal levels. Moreover research studies should take the menstrual cycle phase in consideration which may be a confounding factor in framing and concluding studies on reproductive age group women.