title: Unexplained pain during epidural analgesia.
mesh_terms: D000328:Adult; D000767:Anesthesia, Epidural / Q000009:adverse effects*; D000773:Anesthesia, Obstetrical / Q000009:adverse effects*; D001415:Back; D005260:Female; D006801:Humans; D010146:Pain / Q000209:etiology*; D011247:Pregnancy