First month: After the fertilized egg is laid, it grows day by day as seen from the mother’s body. One month there is an embryo, a small white transparent body, roughly divided in shape into two parts, head and tail, less than 1 cm in total length and weighing about 1 gram, but its heart, neural tube and blood circulation in its original form have begun to occur. At the end of the third week after fertilization, the heartbeat and blood circulation begin to appear, and at the end of the fourth week, the respiratory system begins to develop. At the end of the second trimester, the embryo is about 3 cm long and weighs 4 g. The embryo has a human form, the head and trunk are distinguishable, the limbs are beginning to appear, the neural tube is bulging, the brain is developing rapidly, and the heart, liver, stomach and intestines are taking shape. In the third trimester, the fetus is about 9 cm long and weighs 18-20 g. The fetus has the first human shape, the head is larger, the five senses are beginning to develop, the limbs are beginning to move slightly, and the hands and toes are clearly differentiated. From the appearance of the male and female can be distinguished, the kidneys began to secrete, endocrine glands can secrete a small amount of hormones, small intestine peristalsis, the skin is extremely thin and transparent. In the fourth month, the fetus reaches 16-18 cm in length and weighs about 120 g. It grows rapidly, the ratio of the fetal head to the body is so disparate, the legs are relatively longer, and the bones are rapidly ossifying. Under the function of liver, stomach and intestines, green fetal stool has been formed, which will be excreted only after birth. Fetal hair appears on the skin. The heart rate is twice that of an adult. The fifth month: The pregnant woman will feel the fetus in her belly kicking itself to show its presence, this is fetal movement. Another message from the fetus is that fetal heart sounds can be heard in the abdomen, usually 120-160 beats per minute. The fetus has the ability to hear and can start fetal education. At this time, the fetus is about 25 cm long and weighs 500 grams. The sixth month: length is about 31 cm, weight is 600-700 grams, head circumference is about 22 cm, five senses have developed, face is clear, skin is thin, subcutaneous fat increases, tooth base begins to erupt, and limbs are active. Seventh month: length about 34 cm, weight about 1000-1200 g, head circumference about 26 cm, skin thinner, slightly reddish, more wrinkled, resembling little old man. Skeletal muscles are more developed, visceral function is gradually improved, the eyelids can be separated, the nervous system has been involved in physiological regulation, but the lungs are not well developed, if born at this time, often respiratory difficulties, weak vitality, not easy to survive, requiring careful care and feeding. The eighth month: length of about 42 cm, weight 1700 grams, head circumference of about 30 cm, shape and internal organs are generally perfect, fetal hair reduced, the skin is light red, more fetal fat, more wrinkles, fetal brain, stomach, intestines, lungs, kidney development is close to maturity. The fetal position has been fixed at this time, the normal position is head down hip up flexed position. If born at that time, as long as carefully raised, can survive. Ninth month: length of about 47 cm, weight about 2400 grams, head circumference of about 33 cm, subcutaneous fat, the body becomes plump, skin wrinkles reduced, the whole body of the fetal hair has gradually faded, the genitals have been well developed, the testes have descended into the scrotum, the function of the internal organs have been more mature. They can survive away from the mother’s body. The tenth month: the body length is about 51 cm, the head circumference is about 35 cm, the weight is about 3100 grams, the hair is silky, the head is harder, the ears are clear, the soles of the feet are covered with textures, the nails are also up to the fingertips, the internal organs, muscles and nerves are all developed and mature, and can survive independently from the mother.