Pre-labour pains are mediated through?

Pain during the first stage of labor is mostly visceral pain resulting from uterine contractions and cervical dilatation. It is usually initially confined to the T11-T12 dermatomes during the latent phase but eventually involves the T10-L1 dermatomes as the labor enters the active phase. The visceral afferent fibers responsible for labor pain travel with sympathetic nerve fibers first to the uterine and cervical plexuses, then through the hypogastric and aoic plexuses before entering the spinal cord with the T10-L1 nerve roots. The pain is primarily in the lower abdomen but may increasingly be referred to the lumbosacral area, gluteal region, and thighs as labor progresses. Also Know: Pain during the second stage of labor involves the T10-S4 dermatomes. Ref: Morgan, Jr. G.E., Mikhail M.S., Murray M.J. (2006). Chapter 43. Obstetric Anesthesia. In G.E. Morgan, Jr., M.S. Mikhail, M.J. Murray (Eds), Clinical Anesthesiology, 4e.