Triglyceride Levels During Menstruation
Triglyceride levels typically do not show significant changes during menstruation, and lipid screening can be performed without standardization to menstrual cycle phase. 1, 2
Evidence on Triglycerides and Menstrual Cycle
The relationship between triglyceride levels and menstrual cycle phases has been studied with somewhat mixed results, but the highest quality and most recent evidence indicates minimal clinically significant variation:
American Heart Association Scientific Statement: Recent studies have reported no change in basal VLDL triglyceride and apolipoprotein B-100 kinetics and triglyceride levels during the menstrual cycle, while other studies have shown small changes but with overall coefficients of variation similar to those of postmenopausal women and men 1
Modern Clinical Practice: Screening and risk assessment in premenopausal women can be performed without standardization of lipoprotein measurements to the phase of the menstrual cycle 1, 2
Physiological Research: A 2006 study specifically examining VLDL-triglyceride kinetics found no effect of menstrual cycle phase on triglyceride metabolism 3
Conflicting Evidence
Some older or smaller studies have reported variations in lipid levels during the menstrual cycle:
A 1991 study observed fluctuations in cholesterol levels during different phases of the menstrual cycle, with triglycerides showing similar fluctuations but not reaching statistical significance 4
A 2017 study found lower triglyceride levels in the luteal phase compared to the follicular phase, though the difference was not statistically significant (p=0.18) 5
A 2008 Italian study (Progetto ATENA) found that women with longer menstrual cycles (30-31 days) had higher triglyceride levels (116 mg/dl) compared to women with shorter cycles (21-26 days, 106 mg/dl) 6
Clinical Implications
The evidence suggests several important clinical considerations:
Practical Approach: Lipid screening can be performed at any point during the menstrual cycle without significant impact on clinical decision-making 1, 2
Coefficient of Variation: Any small changes in triglyceride levels during the menstrual cycle are within the normal biological variation seen in both men and women 1
Risk Assessment: For cardiovascular risk assessment in premenopausal women, the phase of the menstrual cycle does not need to be considered when measuring lipid levels 2
Special Considerations
Hormonal Contraceptives: Oral contraceptives can significantly increase triglyceride levels (20-30% on average, up to 57% in some populations) 1
Polycystic Ovarian Syndrome: Women with PCOS have higher triglyceride levels than women with normal premenopausal physiology, even after correction for BMI 1, 2
Perimenopause: Triglyceride levels increase during perimenopause (approximately 9.0% increase, 3.2% after adjustment), with peaks during late perimenopause/early postmenopause 2
Pregnancy: Significant "physiological hyperlipidemia" occurs during pregnancy, with 2-fold increases in triglyceride levels during the third trimester 1
In conclusion, while some minor fluctuations in triglyceride levels may occur during different phases of the menstrual cycle, these variations are not clinically significant enough to warrant timing lipid testing to specific phases of the menstrual cycle.