Chantelle Houghton has announced that she is 11 weeks pregnant with her first child and that the baby was conceived naturally.

The former Celebrity Big Brother housemate was told by doctors that fertility problems meant she would have difficulty falling pregnant without IVF.

Chantelle revealed her happy news to OK! magazine, saying she found out four weeks ago, just after boyfriend Alex Reid proposed to her.

At the time of her positive pregnancy test, she was about to start IVF after spending “thousands” on private fertility treatment because of what health professionals had told her about her chances of falling pregnant naturally.

She told OK! her doctor responded to her happy news by saying: “Well, you’ve proved them wrong, haven’t you?”

Chantelle added: “But then again, maybe it really is a miracle.”

The couple started trying for a baby in August, having been together since May.

At first, Chantelle was nervous about revealing the extent of her fertility problems to her new boyfriend. She said years of crash dieting and suffering from eating disorders have exacerbated the issue.

Scientists from King’s College London found that women who had suffered from anorexia or bulimia were likely to take longer to fall pregnant than others and were more likely to need treatment to conceive a baby.

However, it also found that women with anorexia are more likely than the average population to fall pregnant unintentionally.

Lead author Abigail Easter from the Institute of Psychiatry at the institution commented: “The high rates of unplanned pregnancies in women with a history of anorexia suggest that women may be underestimating their chances of conceiving.”

Maintaining a healthy weight is important for fertility. The NHS points out that some underweight women might find that they get their periods infrequently or that they stop altogether, which increases the risk of future fertility problems.