Inverted nipples are those that are withdrawn below the surface of the skin and lack the normal protrusion. Nipple inversion is a condition you’re born with. If you’ve had them all your life, inverted nipples are usually harmless, though they can sometimes make breastfeeding more difficult.
Thereof, what causes flat nipples?
An inverted or retracted nipple is often congenital, meaning it has been present since birth. This can occur in both females and males. In most cases, it affects both sides. It results from tight connective tissue or issues with the ductal system connecting to the nipple.