The most common reason for nipple blanching is that that baby is compressing the nipple while nursing. This can be due to:
*a shallow latch (the most common problem)
*baby clamping down to slow a too-fast let-down
*baby clamping due to allergies
*clampdown bite reflex
*palate variations, etc.
When blanching is due to baby's compression of the nipple, the nipple is white and often misformed (flattened, creased, pointed, etc.) immediately upon coming out of baby's mouth. There may be a white stripe across the nipple directly after nursing. Pain may not start until a few seconds to a few minutes after nursing, as the circulation returns to the nipple. If you are experiencing pain with the blanching, then finding and remedying the underlying cause will also eliminate the blanching.