Obstetric analgesia; a new machine for the self-administration of nitrous oxide oxygen.
D016362:Analgesia, Obstetrical; D000758:Anesthesia; D000776:Anesthesiology; D005260:Female; D006801:Humans; D009609:Nitrous Oxide; D010100:Oxygen; D011247:Pregnancy
D009609:Nitrous Oxide; D010100:Oxygen
ANESTHESIA/nitrous oxide