Image caption The new IVF rules come into effect on 1 July

Couples in Scotland who need help conceiving will be guaranteed two free infertility treatments from 1 July.

The new IVF criteria has been approved by the Scottish government, but there will be restrictions.

The treatment will only be available to those under 40, and it will not be offered to women who are obese.

In addition, couples need to have been in a stable relationship for two years and neither partner can smoke for three months before treatment begins.

Both partners also need to be methadone-free for a year before IVF starts.

Women aged between 40 and 42 will be eligible for one cycle of fertility treatment if they have never previously undergone the procedure.

We also have to be responsible about the effects of smoking and obesity on pregnancy and beyond Michael Matheson, Scotland's Public Health

The guarantees came as the National Infertility Group published a report with recommendations on new criteria.

The eligibility criteria for free fertility treatment in Scotland currently includes a female age limit of 39; the patient must not already have a child living at home; and they must have had less than three previous funded embryo transfers.

Scotland's Public Health Minister Michael Matheson said the government was committed to "providing fair, reliable and faster access to IVF treatment".

He insisted that it was important to end the different approaches across the country and to offer "equity".

Mr Matheson explained: "For the first time NHS provision of IVF will not vary, regardless of where you live.

"All patients in Scotland will have access to a more generous and fairer service than elsewhere in UK.

New IVF criteria A guaranteed maximum of two full cycles of IVF, as well as unlimited frozen transfers for eligible couples until the woman's 40th birthday Women aged between 40 and 42 will be offered one full cycle of IVF provided they meet all necessary criteria

From 31 March, 2015, all eligible couples will start treatment within 12 months of being accepted for IVF treatment Obese women - those with a Body Mass Index (BMI) over 30 - will have to lose weight and have a BMI of 29.9 or less before treatment If either partner smokes they will need to have stopped before treatment is commenced

"We are investing £12m over three years to help drive down waiting times for IVF treatments, and waiting times are already reducing in a number of NHS board areas.

"We also have to be responsible about the effects of smoking and obesity on pregnancy and beyond. Smoking not only reduces the effectiveness of IVF, but also doubles the risk of pregnancy loss.

"NHS boards will offer patients the support needed to make the lifestyle changes demanded of the new criteria.

"The safety of mother and baby is of utmost importance and the recommendations will ensure healthier outcomes for both families and babies born as a result of IVF treatment."

The guidelines for NHS fertility treatment in England and Wales changed earlier this year.

The National Institute for Health and Clinical Excellence said the upper age limit should rise from 39 to 42 in England and Wales, with women under 40 being offered three cycles of IVF.

Gwenda Burns, from Infertility Network Scotland, welcomed the changes, which unlike in England and Wales will be enforceable in Scotland.

She added: "For too long patients have faced a postcode lottery.

"We are delighted that this report and recommendations by the minister will ensure we now have a fair and equitable service throughout Scotland."