title: Analgesia during labour: a comparison between dihydrocodeine and pethidine.
mesh_terms: D000328:Adult; D000773:Anesthesia, Obstetrical; D002986:Clinical Trials as Topic; D003061:Codeine; D005260:Female; D006801:Humans; D007273:Injections, Intramuscular; D008614:Meperidine / Q000627:therapeutic use*; D010919:Placebos; D011247:Pregnancy
chemical_list: D010919:Placebos; D008614:Meperidine; D003061:Codeine