Requirements of an ideal analgesic and the use of nitrous oxide and trichlorethlene in childbirth. A pregnant woman is shown on a hospital bed and the voice-over sets the tone for this medical information film, explaining that there are four key factors in seeking analgesia in childbirth. The mother remains conscious and co-operative, there are good uterine contractions, the method is safe for mother and baby and respiration in the baby is not repressed. Reminding the viewer of the happy outcome of labour, the mother is shown with her new baby.