Narcotic analgesics and delayed gastric emptying during labour.

The rate of gastric emptying in women during labour was estimated indirectly from the kinetics of absorption of orally administered paracetamol (acetaminophen). Gastric emptying was normal in patients who had not received a narcotic analgesic but was markedly delayed in women given pethidine, diamorphine, or pentazocine. The inhibitory effect of diamorphine and pethidine on gastric emptying was not reversed by metoclopramide.