Many women have low erythrocytes during pregnancy when they have routine blood tests. The main reasons for this phenomenon are: 1. the lack of protein nutrients and iron intake due to severe pregnancy vomiting or deliberate dieting, partial eating, picky eating, etc., which leads to insufficient synthesis of hemoglobin and red blood cells, resulting in low red blood cell count in blood; 2. blood dilution: after the middle and late pregnancy, due to the increase of circulating blood in pregnant women, the blood is in a relatively dilute 2. Hemodilution: After the middle and late pregnancy, due to the increase of blood circulation in pregnant women, the blood is in a relatively diluted state, which will also cause the red blood cell and hemoglobin count in the blood to decrease. A slight decrease is physiological and does not require special treatment, while a significant decrease is pathological and requires appropriate treatment.