A girl’s pelvis usually stops growing between the ages of 18 and 20, but it may vary slightly from person to person with different body types. The pelvis is mainly composed of the hip bones, sacrum, and coccyx. The female pelvis has a rounded upper opening, a wide lower opening, and a short, wide pelvic cavity, which serves as the birth canal for the fetus during labor. Generally speaking, a girl’s pelvis starts to develop between 9 and 11, and stops growing between the ages of 18 and 20, but it cannot be ruled out that the pelvis stops growing after the age of 20 or between the ages of 18 due to the differences in individual physique. The closure of the pelvis includes the closure of the pelvic joints and the closure of the pelvic epiphyses, and the closure of the pelvis indicates the end of growth and development. When pelvic growth is abnormal, it is necessary to consult a doctor and follow the doctor’s instructions for appropriate treatment.