title: Letter: Patient-controlled intravenous narcotic administration during labour.
mesh_terms: D000701:Analgesics, Opioid / Q000008:administration & dosage*; D000773:Anesthesia, Obstetrical; D005260:Female; D006801:Humans; D007275:Injections, Intravenous; D011247:Pregnancy
chemical_list: D000701:Analgesics, Opioid