The size of a fetus in the seventh month of pregnancy is one that weighs about 1,000g, while its length is about 35cm. The size of the fetus in the seventh month of pregnancy corresponds to the fetus in the 28th week of pregnancy, and the size of the fetus at this time can be assessed by a variety of indicators, such as the weight of the fetus at this time is about 1,000g, the length of the fetus is about 35cm, the parietal length of the top of the buttocks is 25cm, the biparietal diameter of the head is 7.46cm, the head circumference of the head is 26.37cm, the femur length of the femur is 5.29cm, etc., and the specific size of the individual differences exist, and generally up and down is not more than two standard deviations. The general range is not more than two standard deviations up or down. When the size of the fetus obviously exceeds the level of the same pregnancy, the gestational week should be verified in a timely manner, to clarify whether the mother has gestational diabetes mellitus and other diseases; when the size of the fetus is obviously small, in addition to re-verification of the gestational week, need to be further examined to clarify the presence of intrauterine growth retardation and other diseases. If abnormalities occur, pregnant women should be treated under the guidance of specialized physicians to avoid delays that could lead to adverse pregnancy outcomes.