Cyclic changes in HIV shedding from the female genital tract during the menstrual cycle

Factors increasing genital human immunodeficiency virus (HIV) shedding may increase female-to-male HIV transmission risk. We examined HIV shedding in 67 women with HIV type 1 and herpes simplex virus type 2 coinfection, during 2 menstrual cycles. Shedding occurred in 60%, 48%, and 54% of samples during the follicular, periovulatory, and luteal phases, respectively (P = .01). Shedding declined after menses until ovulation, with a slope -0.054 log10 copies/swab/day (P < .001), corresponding to a change of approximately 0.74 log10 copies between peak and nadir levels. Shedding increased during the luteal phase only among women with CD4 counts of <350 cells/µL. In reproductive-aged women, shedding frequency and magnitude are greatest immediately following menses and lowest at ovulation.