Women have been warned of the dangers of being too thin if they are trying to fall pregnant.
A new study has found that being too skinny is worse than being overweight when trying for a baby.
Fertility specialist Richard Sherbahn who undertook the research, said the attention given to the dangers of being obese means that the issues connected to thinness are often ignored.
Dr Sherbahn, who works at the Advanced Fertility Center of Chicago, examined 2,500 IVF treatments that were carried out at his clinic over eight years.
The women were separated into three groups by their weight – very thin, normal and obese.
Fifty per cent of those in the normal weight group had babies, as did 45 per cent of those in the obese group, but just 34 per cent of those classed as very thin became mothers.
Dr Sherbahn said he was 'surprised' the effect being underweight had on fertility, saying women are unlikely to be aware that it can be more damaging to be too thin rather than too fat:
'I am no expert on the sociological side of it but I have a teenage daughter and it seems that girls idolise models who are anorexic-looking.
'It seems that the ideal body structure for young women is this overly-skinny physique and women don't understand that there is any concern about that.'
He concluded that women trying to conceive, either naturally or with fertility treatment, should try to get as close to their ideal weight as possible.
Did you struggle to conceive because of weight issues?