The organs of a child in the fourth month of pregnancy are not well developed. The fetus in the fourth month of pregnancy, that is, the fetus in the 16th to 17th week of pregnancy, at this time the fetus has a human appearance, but the organs are not well developed. At this point, the fetus is already in the middle of pregnancy, the length of the fetus is about 16 to 17 cm, the top hip length is about 12 cm, and the weight is about 110 g. At this point, you can identify the sex of the fetus by the external genitalia, the liver is starting to develop and produce bile, and the kidneys are also starting to produce urine. At this time, the fetus has appeared respiratory movement. At this time, although the fetal organs are beginning to take shape, they are not yet fully developed and are in the stage of rapid development. Therefore, pregnant women at this time should pay attention to strengthening nutrition, ensuring sufficient protein and other nutrients intake, and under the guidance of the doctor for regular obstetrical examination, so as to ensure the normal development of the fetus.