Vertebral Subluxation is a term used to describe when their's a bone out of place which irritates delicate nerve tissue. The changes associated with pregnancy can aggravate or even cause a vertebral subluxation. The hormone relaxin is released when a woman is pregnant, relaxing her joints making it easier for the body to prepare for delivering a baby. This can also make it easier for her joints to become out of place and irritate the nerve tissue. One woman described the feeling of hearing her joints move in her sleep as a "shotgun" going off up and down her spine and pelvis. Research has shown that as many as 56% of pregnant women experience back pain which can be a sign of subluxation. Pregnancy should be a time to reflect on your family's goals and dreams - not a time to be burdened with pain.