What is the reason for the pain in the nipples during pregnancy? The first factor is the change of sex hormones during pregnancy, that is, the continuous increase of progesterone and estrogen, which will cause the gradual enlargement of the breasts, resulting in some melanin deposits around the nipples and some hard nodules that can cause nipple pain, this pain is generally a physiological phenomenon, do not worry. In the second case, there may be a lump in the breast that causes nipple pain, so you can go to a regular hospital breast surgery for an examination and, if necessary, a mammography and mammogram to clarify the specific diagnosis according to the test results and deal with it in a targeted manner. The third situation is that the nipple area may also have a painful nipple due to skin infection, so you need to pay attention to skin cleanliness and keep the nipple dry and hygienic.