BBC News Online: Health

'Anything with your gym shoe, madam?'

A poll of 200 pregnant women in the UK for vitamin makers Sanatogen found some had eaten the most extraordinary things, including children's gym shoes and burnt matchsticks.

Others stuck to items that are more often considered edible - but only just. They included:

• ice lollies dipped in mustard
• custard-covered beetroot
• garlic bread with strawberry yoghurt
• chocolate mixed with salad cream
• stuffed olives with lemon curd
• chocolate ice cream with prawns and pineapple
• coffee granules on crumpets

A spokeswoman for the Maternity Alliance said: "Most things are absolutely fine to eat and there is no problem.

"If a craving does seem very bizarre it is always worth checking with your doctor or midwife, especially if you are eating a lot if it and are maybe not getting a balanced diet."

Cravings theory

Sarah Schenker, a dietician at the British Nutrition Foundation, said the reason for cravings during pregnancy had never been fully established.

But she said there was a theory that the human body was innately aware of what foods it most needed to provide essential nutrients, and manufactured cravings to fulfil those needs.

She told BBC News Online: "This sense could be heightened during pregnancy, where there is an increased requirement for nutrients."

Ms Schenker said it was also possible the hormonal changes associated with pregnancy, coupled with mood swings could combine to produce cravings for bizarre foods.

She said it was possible pregnant women desired food that had happy associations for them, and conversely avoided food linked to unhappy memories.

Cravings for gym shoes or burnt matches were more likely to be linked to smell, rather than taste, she said.

"When her hormones are all over the place, it might be that a pregnant woman is attracted by a very strong smell that would not be at all attractive to the rest of us."