[Obstetrical analgesia with premixed N2O/O2].
D000773:Anesthesia, Obstetrical / Q000379:methods*; D005260:Female; D006801:Humans; D008614:Meperidine; D009609:Nitrous Oxide; D010100:Oxygen; D011247:Pregnancy; D011398:Promethazine
D008614:Meperidine; D011398:Promethazine; D009609:Nitrous Oxide; D010100:Oxygen