Lumbar pain when standing up for a long time and pregnancy?

Physiologic and : Structural changes occur during pregnancy that affect the musculoskeletal system, your body secretes a hormone, relaxin, that allows for some ligament laxity to allow for expansion of your birth canal at the pelvis level. As the fetus grows, your center of gravity shifts affecting your posture which places an increased load onto your lower back which can lead to back pain with prolonged standing.