The pubic symphysis is the joint in the midline of the pelvis that connects both sides of the body. It moves very little and acts mainly to provide stability to the pelvis allowing from smooth transfer of forces between the trunk and lower body including shock absorption. It also allows for weight transference and acceptance between right and left legs during activities. Dysfunction and pain of the pubic symphysis is also called pelvic girdle pain.
The pubic symphysis has 2 mm of movement and 1 mm of rotation available. During childbirth the pubis symphysis becomes more lax allowing for delivery of the baby. Up to 9mm of total width between each side of the pubic symphysis is considered normal for pregnant women. This should decrease after birth and return to within normal limits postpartum. Sometimes this separation remains after delivery which is termed a pubic symphysis diastasis. Factors that influence a diastasis include forceps use during delivery, a rapid birth, multi-pariety, previous pelvic trauma, and maternal hip dysplasia.