The measurement of the gestational sac has only 2 data of length and width usually because the development of the fetus is not yet complete at this time, so only flat measurement is performed. Generally, the gestational sac is measured in three dimensions, i.e. length, width and height, but when the fetus is not yet fully developed, in order to avoid errors, only planar measurements are taken, i.e. only 2 dimensions are measured, i.e. length and width. According to the size of the gestational sac can roughly estimate the gestational week of the mother’s pregnancy as well as the development of the embryo, due to the different growth and development of different fetuses, generally the size of the gestational sac can be within the normal range. During pregnancy, it is important to have a healthy diet with proper nutrition, eat more fresh fruits and vegetables and foods high in protein, and keep your mood happy. In addition, regular pregnancy checkups are needed to rule out the possibility of fetal abnormalities, and any abnormalities should be consulted promptly.