Influence of low-dose oral contraception on peripheral blood lymphocyte subsets at particular phases of the hormonal cycle

Objective: To investigate the effects of low-dose oral hormonal contraception on the immune system during certain phases of the hormonal cycle. Design: Prospective, nonrandomized, controlled study. Setting: Academic research setting. Patient(s): Women with regular menstrual cycle using hormonal oral contraception (OC; Cileste(R), 250 mug of norgestimat and 35 mug of ethinylestradiol, or Marvelon(R), 150 mug of desogestrel and 30 mug of ethinylestradiol) and women not using hormonal or other forms of contraception. Intervention(s): Peripheral blood lymphocyte subsets were determined by flow cytometry on the first day of menstruation (day 1). in the follicular phase (day 8), midcycle (day 15), and in the luteal phase (day 22). Main Outcome Measure(s): Levels of lymphocyte subpopulations. Result(s): Women using OC had significantly higher levels of CD3 + CD8 + cells throughout their pill cycle compared to controls. Furthermore, women taking Cileste(R) had lower levels of natural killer (NK) cells during their cycle and also women taking Marvelon(R) but only from days 8-15. Within the pill cycle of Cileste(R) we observed an increase in CD20+ and CD20+ CD5+ cells from days 1-8. Conclusion(s): Cytotoxic lymphocytes, which are responsible for first-line immune defense, and B cells, which are involved in autoimmune disorders, are affected by OC. (C) 2002 by American Society for Reproductive Medicine.