Per Breastfeeding and Human Lactation (Riordan, 2004, p. 80), "Small amounts of milk or serous fluid are commonly expressed for weeks, months, or years from women who have previously been pregnant or lactating." The amount is most often very small, however, and spontaneous flow (leaking) generally stops within 2-3 weeks. Mothers who have breastfed for a longer duration may be able to express milk for a longer time after weaning. Any stimulation, e.g. checking to see if milk is still there, frequent breast self-exams, friction from a bra , stimulation during intercourse, etc., can cause further production.