The most common causes include bladder or bowel over-distension from urinary retention and fecal compaction, pressure sores, extreme temperatures, fractures, undetected painful stimuli (such as a pebble in a shoe), sexual activity, and extreme spinal cord pain.
ðə mˈoʊst kˈɑːmən kˈɔːzᵻz ɪŋklˈuːd blˈædɚ ɔːɹ bˈaʊəl ˌoʊvɚdɪstˈɛnʃən fɹʌm jˈʊɹɹɪnˌɛɹi ɹᵻtˈɛnʃən ænd fˈɛkəl kəmpˈækʃən, pɹˈɛʃɚ sˈoːɹz, ɛkstɹˈiːm tˈɛmpɹɪtʃɚz, fɹˈæktʃɚz, ˌʌndɪtˈɛktᵻd pˈeɪnfəl stˈɪmjʊlˌaɪ sˈʌtʃ ɐz ɐ pˈɛbəl ɪn ɐ ʃˈuː, sˈɛkʃuːəl æktˈɪvᵻɾi, ænd ɛkstɹˈiːm spˈaɪnəl kˈoːɹd pˈeɪn.