At 25 weeks of gestation the fetus has a biparietal diameter of about 6.2cm, a head circumference of about 23cm, a body weight of about 750g or so, wrinkled skin and the appearance of eyebrows and eyelashes. With the increase of pregnancy weeks, fetal development is also gradually perfected, in 25 weeks of pregnancy, the fetus has a length of about 30cm, the biparietal diameter of about 6.2cm, the head circumference of about 23cm, abdominal circumference of about 20.4cm, weighing about 750g, due to the subcutaneous fat content of the skin is not much crinkled, and the emergence of eyebrows and eyelashes. At this time, fetal alveoli and fine bronchioles have developed, and after birth, there can be breathing, but the viability is very low. With the increase of pregnancy weeks, fetal growth and development of the nutrients needed will be more and more, since the middle of pregnancy should be under the guidance of the doctor to increase the appropriate amount of protein, calcium, iron and vitamins and other nutrients rich in food, such as meat, eggs, dairy products, poultry and fish, etc., in order to ensure that the diet of balanced nutrition.