Back and pelvic girdle pain from prepregnancy to postpartum: a new pain tracking method considering pain intensity and chronological patterns. - Iguchi T; Kakutani K; Souda H; Kinoshita K; Funada N; Tomatsuri M; Sadamitsu T; Yurube T (European spine journal : official publication of the European Spine Society, the European Spinal Deformity Society, and the European Section of the Cervical Spine Research Society, 2025)