The changes of nipples in early pregnancy are mainly as follows: Firstly, nipples will become hard and red in early pregnancy because of the changes in hormone levels in the body, the ratio of progesterone and sex hormones is elevated, which promotes the development of breasts, and nipples will become hard and red. Secondly, some people will have pigmentation on their nipples, which is a normal physiological phenomenon. The vigorous metabolism in the body leads to the deposition of metabolites on the skin surface, resulting in increased pigmentation on the nipples. Thirdly, the nipples may become sensitive. After pregnancy, the breasts start to develop faster and the nipples also develop, and the nerve endings of the nipples develop rapidly, resulting in more sensitivity to external stimuli. Fourth, some people may have small erosions and ulcers on their nipples, which is a normal physiological phenomenon and is also caused by changes in hormone levels in the body during pregnancy, so pay attention to hygiene and prohibit scratching to prevent aggravating infection.