Spotting during pregnancy is a very common physiological phenomenon, and the common reasons are as follows: First, infection is easy to happen during pregnancy, women’s bodies are in a state of allergy when they are pregnant, and they are easily infected by the outside world. If infected at this time, it may lead to the toxins in the body to manifest on the surface, forming pigment is pigmentation. Secondly, the hormone level in the body has changed significantly. When pregnant, the sex hormone and estrogen in the body have changed greatly, and the endocrine secretion is easily damaged at this time, so it is easy to grow spots. Thirdly, the mental tension and anxiety of pregnant women and the nervous system allergy have certain relationship, some of them may be prone to insomnia and even anxiety, which will lead to metabolic disorder in the body and also easy to form pigment and eventually grow spots. Fourthly, changes in diet structure, the nutrition supply of mother’s body is greater than usual when pregnant, and the metabolism of material is more vigorous, so the increase of waste in body and the obstacle of excretion will also lead to the growth of spots in body, especially the pigment of face is more likely to accumulate.