The immune systems of pregnant women work less effectively than normal in order to prevent the body rejecting the foetus. One of the effects of this is that pregnant women are more susceptible to traveller’s diarrhoea. Furthermore the pathogens which cause the diarrhoea are not killed off in the stomach as it produces less acid. The working of the bowels also slows down during pregnancy which means the pathogens can live longer than normal. One of the main risks of traveller’s diarrhoea is dehydration, and this in turn reduces the blood flow to the placenta making the maternal blood more acidic. This can jeopardise the pregnancy and even lead to the death of the unborn child.

The most effective way to avoid traveller’s diarrhoea is to wash the hands after every handshake and before every meal. Water which may have been contaminated should be boiled before use or decontaminated using an iodine solution; although the latter should only be done in case of emergency, if no other method is available. All meat should be well cooked and dairy products should be pasteurised. Contaminated water and food can also transmit Hepatitis E. This disease has a mortality rate among pregnant women of 25 per cent. Vaccinations are available against some but by no means all pathogens which cause diarrhoea.