A small pelvis is a pelvis with narrowing in all three planes of the pelvic inlet, mid-pelvis, and pelvic outlet, with a diameter of less than 2 cm or more. When a woman goes into labor, the narrowing of the pelvis will narrow the passageway for the delivery of the fetus, and then the problem of difficult labor may occur. It does not usually affect normal life or the growth and development of the fetus. Small pelvis is mostly caused by short stature. The human body’s pelvis is composed of the right and left hip bones, sacrum and coccyx, which can be divided into large and small pelvis by the boundary of the ring formed by the sacral cape, arch line, pubic comb, pubic symphysis, pubic symphysis, and pubic symphysis joint upper edge. The pelvic cavity can accommodate organs such as the uterus, ovaries, bladder, ureter, and urethra. When the body stands, the plane of the upper pelvic opening tilts forward and downward, and the tilt is slightly greater in women than in men.