title: An assessment of the analgesic effect in labour of pethidine and 50 per cent nitrous oxide in oxygen (Entonox).
mesh_terms: D000698:Analgesia / Q000145:classification; D000773:Anesthesia, Obstetrical; D005260:Female; D006801:Humans; D007743:Labor, Obstetric; D008614:Meperidine; D009609:Nitrous Oxide; D010100:Oxygen; D010298:Parity; D011247:Pregnancy; D013997:Time Factors
chemical_list: D008614:Meperidine; D009609:Nitrous Oxide; D010100:Oxygen