The patient’s clinical physiologic changes during the 21st week of pregnancy are fourfold: First, the abdomen bulges and the uterus enlarges. At this time, the uterine fundus is approximately flat to the navel or located about one transverse finger below the umbilicus. Second, the patient’s breast changes. The patient’s breasts may appear enlarged and distended, and the nipples are darkened and easily erected. Individuals may have nipple milk overflow, which is mainly caused by the increase of progesterone level and prolactin level after pregnancy, resulting in physiological hyperplasia of the mammary glands and lactation. Third, the patient’s vulva can appear hyperpigmentation, darkening. Fourth, patients can obviously feel the fetal movement. Around 5 months of pregnancy, most women can feel fetal movement. The patient can count the fetal movement every day to observe whether there is any abnormality in the patient as well as the fetus inside the patient’s uterine cavity.