Tickets for the Games which start in just over six months' time went on sale last March, before some of the purchasers discovered they were pregnant, and most events sold out immediately.

Many of the tickets returned on a re-sale website have also been at the top of the price range.

Mothers have expressed frustration and anger on the mumsnet.com website with the chatroom drawing 125 posts and ranking as the most active topic after complaints were first aired earlier this month.

"I'm shocked by the conversation I just had with the London 2012 ticketing people," reported littlepinklizard.

"Our baby is due 2 June, so was enquiring about what I need to do about tickets for the new baby. They said everyone needs a ticket - fine. Children's tickets are 1 - fine.

"But there are no children's tickets for the horse jumping so I have to pay 95 to have a 3 month old in a sling. I said I was planning to bf (breastfeed) and couldn't go without the baby.

"They said the only alternative was to re-sell my ticket or give it to someone else."

LOCOG confirmed the official policy was that everyone entering a venue had to have a ticket.

However, following the complaints and suggestions that the policy was in breach of sexual equality laws, they suggested they could review the situation.

"We want families and young people to come and enjoy the Games, which is why we created Pay Your Age tickets at a third of sessions," said a spokesperson.

"Of course we understand that some new mums may want to take their babies to events they have tickets to, and we will look at what we can do when the remaining tickets go on sale in April."

A million tickets, held back for contingency reasons while venues were tested and licensed, are due to go on sale in April along with returns.

LOCOG has already said it intends to get as many as possible into the hands of those who had failed to get any in previous ballots.

(Editing by John Mehaffey)

• A Permanent Economic Emergency