Gum chewing stimulates early return of bowel motility after caesarean section

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Authors’ Reply

Sir,

We thank Dr H Byrne1 for his interest in our study.2 We used a commercial sugarless, non-sweetened gum, the only ingredients of which are: natural gum, beeswax, and mastic gum (Lentisque). We agree that many of the so-called ‘sugar free’ chewing gums contain substances such as sorbitol, which is known to cause chronic diarrhoea,3,4 and significant weight loss,4 but only on habitual over-consumption (20 g/day or more).3,4 The osmotic laxative effect of sorbitol might – in a small dose – have a beneficial effect. However, we still consider that it is more likely that the enhanced bowel motility results from the direct stimulation of the cephalic-vagal reflex and indirect triggering of the release of gastrointestinal hormones, with increased secretion of saliva and pancreatic juice.2 In support of this hypothesis is the failure to find gum chewing to be efficacious in two studies where epidural analgesia was used. Anaesthetic agents administered via an epidural catheter have been known to be associated with shorter duration of postoperative ileus, possibly as a result of blockade of inhibitory sympathetic reflexes at the spinal cord level. In such cases, it is reasonable to assume that there is little additive effect of vagal stimulation. We consider that the merits of postoperative gum chewing after caesarean section performed under spinal or epidural anaesthesia (with or without postoperative epidural analgesia) deserve further investigation. Other simple and cheap solutions would also be welcome. However, only three systemic prokinetic drugs – alvimopan, intravenous lidocaine or neostigmine – have been reported to have potential value. On the contrary, four studies have addressed the effect of erythromycin and found no evidence of benefit in relation to recovery of postoperative bowel function.5 Furthermore, the possibility of the occurrence of side effects with such drugs should be considered. Gum chewing is a much simpler and cheaper method.

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