I know there have been threads on MN before about black panties getting bleached by wearing them but I have never had it before. It seems (according to my limited research) that it is caused by ammonia from the vaginal tract (not wee leaks - which I don't have).
Basically, I have never had bleached gussets before - but it happened about 2 months ago (a well worn pair that had no sign of bleaching went from jet black to beige in the crotch on one wash). It has happened several times since - old and new ones. I have not changed laundry detergent (dont use conditioner) and it does not always happen. It is not related to monthly cycle or sex (we use condoms - so no sperm in me). After 3 weeks of no bleaching, I have just hung out some washing and a new pair of black Next bikini panties has a virtually white gusset (more towards the back than where any wee might be retained).
Is this the sign of a health issue or some sort of gyno change? Why do I let out ammonia on some days?????