A woman is always permitted to wear white underwear. It is only required during the clean days. But wearing whites is generally discouraged at other times, since a
stain on white undergarments may make a woman
niddah, while the same stain on a colored undergarment could be disregarded.
In other words, you are permitted to wear white undergarments as you wish. We would not recommend doing so, since unexpected staining on white undergarments could make you
niddah. However, you are free to decide whether to take that chance.
Please write back with any further questions.
