Many factors can affect your cholesterol levels -- including genes, certain medical conditions, and diet. But did you know that cholesterol levels were also affected by your menstrual cycle?
This study, published recently in the Journal of Clinical Endocrinology and Metabolism, looked at roughly 260 women of reproductive age over at least two menstrual cycles. Triglyceride levels and cholesterol levels were measured at the same times each month. Home fertility monitors were used to detect ovulation. Lipid levels were tested up to 8 times during each menstrual cycle.
Researchers found that, as estrogen levels increased, "bad" cholesterol levels (LDL) and triglycerides decreased. Addtionally, HDL levels increased with increasing estrogen levels. HDL appeared to be the highest around ovulation, whereas LDL and triglyceride levels were lowest right before the beginning of the menstrual cycle.
This study suggests that the point in a menstrual cycle that a woman is in may influence her cholesterol readings. These changes were modest (between 5% and 8%) but were enough to cause women to be classified with borderline high cholesterol in some cases.
Source: Mumford SL, Schisterman EF, Siega-Riz AM, et al. A Longitudinal Study of Serum Lipoproteins in Relation to Endogenous Reproductive Hormones during the Menstrual Cycle: Findings from the BioCycle Study. J Clin Endocrinol Metab 2010;95:1-6.