Self-administered Entonox (50% nitrous oxide in oxygen) in labour: report of the experience in Ibadan.

The effectiveness, safety and acceptability of self-administered Entonox (50% nitrous oxide in oxygen) in 150 Nigerian women during labour was studied. 86.7% of those who received Entonox alone reported satisfactory pain relief while analgesia was also satisfactory in all those who received Entonox plus intramuscular analgesic. Severe drowsiness occurred in two patients and the method was acceptable to 90% of the mothers in the study. To prevent exhaustion of the mothers and marked drowsiness, intramuscular analgesic should be used early in labour followed by Entonox in the second half of the labour.