Obesity is no bar for success of fertility treatment. Overweight women have as much chance of having a baby that way as normal weight women, a Scottish study suggests.

IVF treatment is no more expensive for most obese women, the report in the journal Human Reproduction added.

But women should be advised to lose weight because of the high risk of complications, the researchers said. And age is certainly a consideration, researchers stressed.

Most primary care trusts limit IVF to women with a body mass index under 30, which excludes women classed as obese.

The research, on 1,700 women who underwent their first cycle of IVF between 1997 and 2006 in Aberdeen, found 28% were overweight, 8% were obese and 5% had a BMI over 35 - classed as heavily obese.

No significant difference was found between groups in the proportion of women having a positive pregnancy test, ongoing pregnancy, and live birth.

And there was no difference in the cost of a live birth between normal weight women and women with a BMI up to 35.

But a higher proportion of women in the overweight or obese groups had a miscarriage.

And they needed higher doses of drugs used to stimulate the ovaries, BBC reports.

Study leader Dr Abha Maheshwari, clinical lecturer in reproductive medicine at the University of Aberdeen, said they had expected costs to be higher in overweight and obese women.