Effects of menstrual cycle and oral contraceptive use on serum levels of lipid-soluble antioxidants.

Objective: The purpose of this study was to examine the influence of menstrual cycle and oral contraceptive use on serum levels of lipid-soluble antioxidants.

Study Design: In this cross-section study, nonfasting blood samples were collected twice from 10 healthy premenopausal women during the follicular phase (between days 8 and 11) and the luteal phase (between days 18 and 22) of their same menstrual cycle. In addition, blood samples from 15 premenopausal women who used oral contraceptive for at least 6 months and 40 women who did not use oral contraceptive were collected randomly at any day of the menstrual cycle.