Nipples can look all sorts of ways—light, dark, big, small, pointing in or out or appearing flat. Truly inverted nipples are caused by adhesions beneath the nipples that bind the skin to the underlying tissues. They're actually quite common; an estimated 10 to 20 percent of women have flat or inverted nipples. For some women, nipple stimulation or cold temperatures can draw the nipples out temporarily.
If you were born with them, inverted nipples don't say anything about your health. You can even breastfeed normally: While babies can have a bit more trouble latching onto an inverted nipple than a protruding one, a little patience while you position yourself and the baby can make it easier for the baby to feed. You can also ask your doctor about special breastfeeding devices, such as breast shells, that help pull out and position an inverted nipple in a way that makes it less difficult for the baby to nurse.
I know this goes without saying, but don't be bothered by how your nipples look. Besides, the only permanent way to change the appearance of your nipples is plastic surgery.
One important caveat: If one or both of your nipples suddenly flatten or turn inward later in life, speak to your doctor about it. A nipple that changes like this can be normal, but it can also be a red flag for certain breast diseases, including inflammatory breast cancer or Paget disease of the breast, a rare type of cancer that involves the nipple and the areola.
Health’s medical editor, Roshini Rajapaksa, MD, is assistant professor of medicine at the NYU School of Medicine.