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White linens during the clean days can show whether a woman is bleeding overnight. However, if a woman wears white undergarments (or white pajama bottoms) to bed, they will catch staining. In that case, the bed linens can be of any color, although some women still maintain the custom to use white.
At any time of month, using white or off-white bedding and linens (including blankets and duvet covers) is fully permissible. It is usually not advisable, though, because a stain on a white surface may make a woman niddah. (Learn more about the halachot of stains here .)
Off-white and ivory are considered shades of white. Beige is considered a colored surface, although it can be difficult to distinguish between pale beige and off-white.
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