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, 250 microg of norgestimat and 35 microg of ethinylestradiol, or Marvelon, 150 microg of desogestrel and 30 microg 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 had lower levels of natural killer (NK) cells during their cycle and also women taking Marvelon but only from days 8-15. Within the pill cycle of Cileste 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.